Good subject. I currently have a basket case 1966 Chevelle convertible (powerglide, mouse motor, bench seat) which I'm selling and I fully expect the eventual buyer to turn into an SS "tribute" car. The reason. of course, is a fake SS will bring about 10-15 grand more at resale than a straight restoration to stock. If everything needs replacing anyway, you might as well spend a bit more on the upgrades while you're at it. Plus, it's a just a much cooler car that way.

You don't see those big differences in buying/selling bikes.

Having said that, I'm contemplating "upgrading" a cheap hi-ten Japanese frame I have in my pile into a fake Legnano, because I'm good with paint and I like the colors. It won't fool anyone who knows anything about Legnanos, but it would be a fun project.