I suspect that there will soon be a lot of bike kits for sale where you purchase the frame and wheels separately. Quick release wheels are a doddle to attach so they could even offer free assembly.
Hm....would kind of be like doing 95% lowers for guns and rifles....they sell you a kit with the lower (that's the part with serial number that is "officially" a gun in the governments eyes)....and the jig so you can finish the last 5% milling out with a drill press, etc.
Example (read towards the bottom of the page)
After that you just get all the other parts to assemble it, which are completely unregulated.
This gets out of some taxes, but most of all, it is a legal weapon without a serial number, and no background check or other hassle from the government. It qualifies as a self made weapon and you don't have to register it, or anything. You can't sell it without having to then do the FFL registration thing, but you are free to possess and use it otherwise without the need for govt. interference..
Its always nice with government regulations, there's usually a way around it.