theyre different. rwd transmissions have bellhousings that is "seperate" from the gearbox, while our FWD cars, the bellhousing is the other half of the gearbox casing. The FWD setup keeps the transmission compact.
prototype racing tried something like that for the Lotus', but ended up just sticking to a K20. It's possible though; this guy over here put a B-series transmission on his H22 by cutting the flange off of the H transmission and welding it to the B transmission. I don't know how reliable it is though, as he never really pushed it after he got that done.