Something already AWD would simplify things....a cheap Imprezza wagon would be worth a look to see if it would fit. Not too hard to get a Nissan diff in the rear to match ratios and survive the torque.
A big job though, not something I'll be tackling anymore I don't think?
You mentioned somewhere on here that you had a 1uz awd sump and trans setup sitting in you shed and trying to think of something to put it in...did you ever think of something??
I also have one in my shed and thinking hard...also have a v8 soarer and 2 x LS400's.