Below are the links collected from across the web to resources to get your project off the ground (well, hopefully not literally).

All Balls: (PA) This company makes bearings to fit almost any bike.  I highly recommend replacing all the bearings when doing a build from a classic bike.  You will be surprised what a difference it makes in the way the bike feels.  And I always order directly from the factory rather than one of the big vendors.

Augie's Art: (NC)  Paintwork extraordinaire.  There are certain links on this list that I am jealous to share with everyone.  This is certainly one.  Augie's work is outstanding and is at home at a concours show or the local gas station.  He makes your project better because you are trying to keep up with the paintwork (although I have quit apologizing to myself).  You can't go wrong here.

Baron's Custom Accessories: (CA ) This site offers custom parts for your cruisers of all models.  I like the billet flame grips they make.  Not on my bike but maybe on yours.

Bike Bandit (CA): This site offers everything for your motorcycle but their real strength is OEM parts.  And I use their microshift constantly while in the garage to figure out how it was supposed to go back together.

Biltwell, Inc. (CA):  These guys offered parts geared towards the garage builder or small shop.  Deeply entrenched in the "built not bought" culture.  Highlights to me are their handlebars and the DIY exhaust kit for Harleys.

Blue Collar Bobbers: (UT)  These guys offer bolt-on bobber kits for a majority of modern cruisers.  While I am all about build it yourself, I must concede there are some guys that just can't turn a wrench and this gives them a chance to build their own bike.  It is what paint by numbers is to portrait work but you know of a guy who needs this help.  Pass this along to them.

Carolina Ceramic Coating:  (NC) I have used these guys to do some pipes and engine parts.  Fast and solid work.  Highly recommend.

Carolina Custom Powder Coating: (NC) This is my buddy Tom Davis' joint and I have to put in a big plug for him.  Not only is Tom that absolutely nicest guy, he is a perfectionist and terrific at what he does.   You can do no better than this.

Classic Components/ South Bay Chrome: (CA) These guys are out of California and do a premium job at a premium price.  I have sent them some real crappy stuff and they sent back show quality parts.  They even did me a solid when I sent them a fender with a wave in it.  Top notch.  Highly recommend.

Custom Dynamics:  (NC) This site features custom lighting solutions for Harleys, Jap. cruisers and your custom.

Debrix Cycles: (CA)  This site offers parts and accesories for Harleys.  There are hard to find custom parts here.

Gennie Shifters: (CO) Old school shift knobs for your Old School suicide shifter.  You know what they say, "If you want to be cool, go old school!"  Actually, nobody says that but they are some nice shift knobs.

HD Wheels: (CA)  If you have to have some sick spoke wheels and your rich uncle just dropped dead and left you a sh*t pile of money, these wheels are out of this world.   Offering custom spoke wheels for almost all American bike applications, they'll even powder coat the spokes for you.

High Rollers Cycle Seats: (NC) Custom seats for any application.  Huge shout out to my man Butch here.   Had a project that stalled when it came to the seat.  Talked to lots of folks with little help.  Finally found Butch and everything turned around.  He asked for some pictures of the bike and I drew some lines for the seat and he was genuinely excited to get it done and got it done fast; better than I could have imagined.  No reason to go anywhere else.  Highly recommend.

HotrodShiftKnob.com: (CO) Unique shift knobs for your suicide shifter.

Koolknobs:  (WY) These guys do some these custom shift knobs which are clear with items embeded in them like scorpions, bullets and eyeballs.  What's not to love.  Limited single orders though so you may have to wait.

Kuryakyn: (WI)  Accessories for Harley and Metric cruisers.  While I personally think bolt-on customization has destroyed the soul of HD, this company does provide good quality parts  - at the prices that are sure to impress everybody at your next Poker Run (I've bought whole bikes for the price of their black chrome license plate bracket).  But if they have the part that is going to make your next project, then God Bless.  

Law Brothers Cycles: (TX)  These guys make custom bikes as well as a bunch of custom parts and will even build you a custom kit.  Repair, paint, fabricating, they are the "fixer" for your project gone wrong.  And their prices are good.  A fender from their seconds bin saved my last project so I am biased I guess.  Winner of the my coolest logo contest as well.

Legends Motorcycles, Inc.: (CO)  This site offers vintage Jap. and Brit. parts but the real story here is tires for vintage bikes.  One of those places that you find something you can't find anywhere else. 

Lick's Cycles:  (MA)  These guys tout themselves as a Harley shop but their online catalog has a lot of parts for your custom project no matter the make.

Lowbrow Customs: (OH )  This site is somewhat of a Mecca in the garage builders' world.  In case you don't know, they offer custom parts for your Harley or Truimph project and are really into the "build it yourself" tradition.  Their frame welding video is a must see!

Lowside Magazine: (MD)  Magazine showcasing garage bike builders and small shops, their bikes and the lifestyle of same.  Great for when you are at work and not supposed to be thinking about motorcycles.

Mike's XS: (FL) This shop offers a variety of parts for the XS650, a popular platform for custom bikes of different design.

Monstercraftsman: (MD)  Ran into these guys at the Timonium show and their parts and finish stood out in a tough crowd.  Tons of parts for your custom ride.

MotionPro:  (CA)  Cables and throttles.  No, there isn't anything exciting about cables but if you change the stance of your bike, you are going to want to get custom cables.  MotionPro will make them for you for not a lot of money and in a pretty quick turnaround (YMMV)

MotorcycleTire.com: (FL)  Great source for motorcycle tires for almost every applications.  I ordered a wide tire from here and when the build didn't come together, they exchanged it for me some time later with no hassle.  Highly recommend.

Omar's Dirt Track Racing, Inc: (CA) Don't let the name fool you.  If you are building a Jap. cafe or street tracker, this is your joint.  And Robert is a great guy to do business with.  I have used their parts on some of my projects and they have a lot of advice after the sale.

Randakk's Cycle Shakk: (NC)  Whether you are restoring a CBX , Goldwing or just stealing the engines for your custom projects (guilty as charged), Randakk will help you get it running better than Honda ever did.

Rebel Highway: (NY)  Motorcycle decals and apparel.  If you hurt yourself changing your oil, maybe custom bike work involves simply putting a sticker on your bike.  And, yes, I was disappointed to find out they were headquartered in NY but they have some cool stuff.

Rock and Ride: (PA)  What's the use of being cool if you are dressed like a square?  Met these nice folks at Timonium (and bought a few of their shirts myself).  Their online store offers lifestyle goods: like t-shirts, leather jackets, old school helmets, etc.  My favorite item is the Triumph chain case clock.  Check them out.

Scootworks: (NC)  These guys build customs from Jap. cruisers and sell a lot of parts to do the same to yours.  Not my thing but it may be yours.

Sebastian Silversmiths: (GA)  These guys offer custom key blanks for your Harley and Jap. bikes.  Cool idea just don't pass out with the Maltese Cross in your pocket (personal experience)

SPD Exhaust: (CA)  For most of us garage builders, exhaust is a problem.  A real pipe bender is out of the question and Harbor Freight versions just won't cut it for a lot of applications.  This shop offers mandrel bends and custom bends so you can "Lincoln Log" yourself together an exhaust system.

Sumax Cycle Products: (NY)  Shop offers custom bike parts for your Harley but the real features are custom spark plug wires and composite fenders

Tapeworks: (NC)  From reproduction to crazy custom graphics, these guys have you covered (no pun intended).  Years ago, I was building a copy of a bike only offered in Europe I had found a picture of.  Stopped in, explained what I wanted and 20 minutes later *MAGIC BANANAS*, I had my decals.  No reason to go ever go anywhere else.

TC Brothers Choppers: (OH) These guys feature parts for building choppers/bobbers out of XS650's (Harley guys, that's a Yamaha) but offer a lot of great parts for whatever your project is.  I have actually contacted them about other applications too and they were real helpful.

Thompson Choppers: (MO)  Makers of frames, rolling chassis and springers for your American iron.

TNR Batteries: (FL)  Distributors of Odyssey and Deka batteries.  These batteries can ship through the mail and, because they are small and sealed, can be mounted anywhere.

Van Chase Studio: Very cool shift knobs for your suicide shifter.  You'll want to keep one eye on the parking lot to make sure nobody steals it.