No, I wouldn't trade it straight across either. But would you trade the 5DII for a 5D and a 35 1.4 or a 5D and a 135L or a 5D and a 24 TSE lens?
Well in my area the 5d1 is about 1,400$ used (roughly) and the 5d2 is about 2,300$ used (again just roughly)
For the lenses you mentioned, Maaybe, not the 135L it does not fit my style, but the other two, maybe... It'd be a tough choice however.