In the windows 8 developer preview there was a registry entry called "RPEnabled" that enabled and disabled the metro interface, reverting it back to a windows 7 esque start menu, network menu and login screen. Unfortunately this registry entry does nothing in the final bulid to my knowledge. So my question is does anybody know if this value still technically exists but is not checked for, or was all the windows 7 stuff removed for good?
That would probably be in a very early build, and was probably only there for if everything broke. I think it would be safe to assume that when they prepared for release they removed most old code. At that point the operating system works must work well enough with the default settings anyway so there's no reason to keep the old stuff.