so you buy the two boxes you need, pay someone to strip both and assemble one using bits from each (and you may as well throw new bearings in while it's apart), modify the tailshaft, x-member, and maybe clutch (if input shaft can't be changed to suit).

you probably may as well do the Dellow alloy case celica 5spd swap which is supposed to be about 10kg lighter (I haven't weighed that box yet) than the Stanza 5spd. This would work out cheaper than the A/L hybrid box if you have to pay someone to do the rebuild.