Changing a worn CJ5 into CJ7

I have dilemma maybe some of you can help me out with. I have both a 68 CJ5 and an 84 CJ7. The CJ5 drivetrain is strong and runs good (except for the constant oil leakage from the 18 transfer case). It has a Buick 350 mated to a T98. The front axle is wide track Dana 44 with a Trutrac. The problem is with the body and frame. The body has stress cracks, dents, minor rust and a poor bondo job (performed previous to my ownership). The frame is bent and has cracks, the clutch arm sticks in the body when the frame twists, and the suspension is rough. Years ago I scored a deal on my CJ7 Laredo due to a broken transmission (T18 replacment is in the garage) and weather rotted interior. I am thinking of transferring the drivetrain of CJ5 into my CJ7. I am somewhat concerned about the legalities. Can this be done in California? I have heard of many people swapping in newer tubs and frames into their Jeeps. This is essentially what I while gaining the benefits of a longer, smoother wheelbase and V8 power. What has been done to maintain the VIN on such swaps?  

I am not sure of the legality of moving the VIN from one Jeep to another in CA, but I don't see whats wrong with rebuilding your CJ-5 with newer used parts. I'd start with a nice westcoast/desert non-rusted YJ frame (its gonna be way stronger than the CJ-5 or the CJ-7s frame and the same length as the CJ-7 tub. You can then pick and choose what parts you want to use from the two Jeeps.  
P.s. I am not Dr. Vern (but I am happy to take credit for his writing!)