yes, well there aren't much in the way of options where is comes to gear boxes, Reg seams to be the one for "new" kits e.t.c.

best would be to deside what you want then see if you can find something second hand.

Another option that I haven't invesigated is apparently in AU you can buy bell housings which will allow at Toyota T50 gear box to be bolted up to the A series engine. the kits for the T50 can be got throught Palmside in CHC and are priced ok.
- perhaps some of our AU friends can comment on the bell housing thing.