They're a great bike with a rock solid engine but the rear end of the frame can make it difficult to use a lot of the bolt on cafe racer parts. However there have been a lot of great builds I've seen on the forum where people have made amazing, unique bikes. Check out the "So you bought a CM400" thread, it has a compilation of a bunch of great builds. I have 79 CM400T that I just "finished" building in September, it's not exactly a cafe but its another example of how versatile these bikes can be. Where there's a will there's a way.