*hmmm* What year? I think almost all of them were unibody - extreme cutting down to the floorpan and drivetrain would seriously compromise it's strength. Not to say you couldn't use it's parts on a tube frame, of course..
Wasn't there one for sale four or five years ago on eBay on the east coast that had a MR2 underneath? I'll have to see if I still saved the photos... it never sold, of course, the seller stating the ubiquitous "needs completed".