I think you should go for it. The black motor idea is a good start, but I've always liked copper, stainless, brushed aluminum accents. It will make it pop instead of being covered in diamonds, or so subdued that its a black hole in the middle of the bike. I know of a place in Mass that sells bronze, and copper pieces for house hardware (door knobs, latches, pulleys) Simple things like antique speo, and tach hands shouldn't be too hard, you could go extreme of copper, bronze, or even gold plating.