eMachineshop.com
Found this the other day, you design your part using their drawing software, choose the type of machine (lathe, 3-axis mill, lazer, etc), material, finish, tolerances and surface treatment like anodizing or cadmium plating etc, they then machine and ship it to you.
If you're used to CAD or the likes you'll find their drawing program very easy to use, I "milled" myself a nice barclamp in about 30 minutes, using 6061 - T6 and anodized it red. Viewed it in 3-D and it looked good!
I tried to get a quote and found out they only ship inside the USA , anyway, it's quite a lot of fun and perfect for "one off billet" jobs.
Like I said, I didn't get a price for my clamp though, so it might be helluva expensive.