The Hyundai Tiburon was simply called the 'Hyundai Coupé SIII' over here, plenty of them about. If you have success with fitting them, let us know, that could be a bit of breakthrough discovery!
Adapting the subframes shouldn't be a major difficulty, the only problem I forsee is making the Ford ECU 'talk' to the airbags in the Hyundai seats. (I'm assuming here that, being from a fairly modern car, the Hyundai seats will have side airbags like the Cougar does.)