You are all mentioning different motors quite close to the SVX in many ways. The TT is the one I would pick as nearest. 4wd, similar hp, 4 seats, both designed as show specials, and later making production.
But there is no room in it. The reason they made a convertible is because the roof was too close to the pedals!
Closer in size and use for me would be the Nissan 300Z twin turbo. But it is more sporty[read noisy and rough] and only 2wd. The Mitsubishi 3000 4wd is also close, has all wheel drive, but same problems as the Nissan.
The Lexus/Toyota 2.5 twin turbo give it a real close run for he money, lots more horses, no 4wd. But is as comfortable to drive long distance.
Nowadays, I think the only car to come close to the experience is the Mercedes CLK coupe. Good size and room, classy coupe styling, and the engine has enough grunt to get you around as quick as you might need. No 4wd, but Mercedes handling is pretty secure. Premium price, but a nice machine.
Bottom line, I agree with Randy. Nothing comes close to the sum of the parts.
Joe
PS If my tranny goes again, I am going to try and stick a BMW or Porche 5 or 6 speed Tiptronic box in it. No more Subaru under-engineering for me, purist view notwithstanding.