I just saw that at SEMA Ford brought a 5L V-8 powered focus making 400 some hp to the rear wheels, so yeah anything is possible with time and money. The engine kit alone was 15 grand drop in and the rest wasn't specified. I think a nice V-6 from the 350z might be shovable into our engine bay, its pretty compact, then just run their tranny back and just make a new drive shaft, blah blah it would be nice.
Back on topic, you could possibly fit it longitudinally IF you could find a tranny that exited the driveshafts at the right area so youd need to find a longitudinal MR tranny(mostly in expensive cars so prolly not cheap). Then youd have an easier time with weight dist, making the chassis stronger, etc. You could just make an extra strong roll cage all around the back which would prolly stiffen her up, just 360 all the fuel lines, run the coolant lines up the transmission tunnel, get an aftermarket vent hood and direct pipe the radiator heat out, mount a racing fuel cell in front as far back and low as possible, make a trunk compartment(if needed) and all the other stuff said and you'd be set. Then punch a hole in the current firewall to give tall people some room in this damn car, then you'd be set ;)
Brent