I do see some of the problems mentioned, but also think you've got an idea worth keeping alive. Here's the greatest example I've ever known of someone doing such a thing. Speedplay Labs
A huge problem here is that, the frame alone, and the paintjob, are the only real distinguishing aspect of many bikes. And of course, many are so similar, that they are often hard to identify (or mis-identify!) when the labels come off. In some cases, if the bikes changed hands, they might be nearly impossible to verify. Look at the Miele in my list of bikes. I painted that in the backyard. It could have been ANY make of reasonably decent frame and really, who would question it?