well, I made one of the ones from 2002 by AMT/ERTL, thread is over here /forums/1104861/ShowPost.aspx
As far as others.. I've seen the Grave Digger from AMT/ERTL's "Monster Jam" line, and it was.. lots and lots of parts, especially for the underside, so it would probably be more detailed. The USA-1 was easy to do but not snap, and they have a Big Foot in the same 2002 line so I'm thinking it'll be about the same challenge. I've read in another thread that the Raminator from Lindberg is really well done and easy to assemble but I know its about twice as much as the others, but I can't say how good it is from personal experience.
Oh, and the older "Thunderbolt One" Chevrolet made by AMT/ERTL was pretty nice too, its even older though so that one is a definate eBay item.