Hi Scott,
Just a couple of things I can help you out with.
1. No you cannot lay the engine over like the deisel.
2. There is a bell housing available as an original part from VW South
Africa. This you can purchase from many sources. I brought mine from a
dealer in Germany, DM 480.00.
3. The engine will stick above the rear deck some 4 cm (1 3/4 inches). In
South Africa the rear deck is 100 mm (4 inches) higher than on our vanagons.
(they also have larger side windows, another mod peculiar to their vans)
4. If you go to Toms relitech site you will find further information on this
type of conversion. Address is http://volksweb.relitech.com, go to:
"conversions air/wasser to other" and choose Helmut Zeidlers air to Audi 5
cylinder conversion.
5. If you have any further questions mail me direct, I am in the process of
doing this conversion myself so can give you all the ins and outs,  however
I have not brought a kit, but am doing it from scratch, the kits a very
exspensive for what they are.
Regards
John.