Talking strictly about the 5 speed. Gear ratios are the same, center boxes look very very similar. Do you think it just takes an NA/NB bellhousing, tail-end and a little know-how? Not sure how the NC trasmission is attached though (PPF and whatnot). Maybe it's more like the gear set from the NC is just removed and placed inside the NA/NB box?
http://nielex.net/maintenance_tmsw.html
NA/NB
NC (bottom)