Anything with an SAE #3 or #2 clutch housing will be extremely easy to use (and probably on the heavy side), as many 53 series come with those size flywheel housings.
There are also ways to adapt NV4500 transmissions to work with the usual GM transmission bolt pattern as found on the SM420, SM465, and T5 transmissions. Then there are stock but sometimes hard to find Detroit housings for the GM transmissions. As well as the Gama Goat housing that takes a GM manual transmission.
Then you have most all the usual automotive transmission options if you use a Phoenix Adapters setup to go from a common SAE #4 Detroit flywheel housing to whatever gas engine bolt pattern you choose.
http://www.phxgrp.com/transmission.htm
Pretty much you can decide what transmission you like and then there will be a way to use it, some methods harder to find or more expensive than others though.
First find out what gear ratios you'll need to use the vehicle like you plan, do you need an Over Drive or not, and then decide what size vehicle and therefore what size transmission should work. By that point you should have considerably narrowed down the list of good transmission choices and you can then see what makes the most sense as far as price, availability, ease of adapting, and personal preference.
Grigg