i like the idea of moving the engine farther back. utilizing a custom tubular crossmember would prevent having to use an oil sump, but also keep in mind the steering rack and assembly is also another obstacle. also this would change transmission mounting which may or may not be a stock item, and would be mounted custom also. moving the engine/trans would move the turbo to in front of the engine (in my mind) to gain the most movement.
battery and other accesories of course are relocated and/or done away with.
the transmission housing mods have been done a lot. i have seen hack jobs in the garage that don't work right or professionally done the right way. the best method i have seen to make these housing is forging them. contacting a local foundry may allow anyone to do this. another method could be a machine shop machining a piece down from suby engine to trans of choice. i have never seen the second option but i have confidence it would work but as far as costs are both are probably expensive.