I used to know a guy that ran an Eclipse at the track with a 350 Chevy RWD... It was quick but not something you'd want to run on the streets. The guy raced without a hood because he would have had to chop it to damn near nothing just for the valve covers, carb, and air cleaner. He welded all kinds of extra supports in the car due to the unibody design (not designed to handle that extra weight) and had to do all kinds of fabrication just to get the whole thing set up. When I saw it at the track, it was all hollowed out and built like a home-grown drag car (basic metal dash, no speedo, etc). His exact words about the car (when I asked why he did it) was this; "Because no one else has!". It was, to put it simply, a disaster.
I guess if you had your own shop, welding/fabricating equipment, and a LOT of time, it might be something to do for a challenge
I can only say this:
If you want a RWD car, buy one and restore it. Have some fun with it. Go crazy and build 1000hp... whatever. FWD cars are great and are a ton of fun to play with, but leave them FWD. You're asking an apple to be an orange. Ask yourself this: if it is that great of a thing to do, why aren't people all over the place doing it? Leave mother nature alone