I found a website yesterday for a group in Aus who are doing interesting work with 5 speed Suby gearboxes.
The sell a replacement crown & pinion set that reverses the gearbox and allows it to be used backwards in a bug.
Also, once the rear nose cone is removed (with the 4wd parts), the case can be shortened quite agressively getting the box down to about 55cm long.
They also sell output flanges that work with 930/944/type2 CV joints.
Getting it to work with a type 4 might be difficult (flywheel/clutch/starter/ etc issues) but if you are planning a suby swap it could save a lot of hassle & money.
The new crown/pinion is about Aus$1500, The output flanges are aus$500 and the part to lock out the 4wd mech is aus$300.
www.subarugears.com