As far as non computer controlled Allison's, all of the New World Allison's are computer controlled, they replaced the AT,MT, HT series starting in about 1996. So to get a non computer controlled Allison you will need one of the mentioned older versions. Another issue is actually fitting the Allison into a light duty truck. The trans tunnels are just too small, Allison trannies are rather girthy. The AT series is physically the smallest and it is a tight fit, the MT is bigger and forget trying to fit a HT. I know of a few companies that have tried to make an aftermarket stand alone controller but they have not worked out very well. Allison will not release the programming to allow for total aftermarket tuning, only some of the parameters can be changed, but without all the rest it just does not work well. So I can't honestly recommend them. I can say Suncoast builds a nice sturdy 1000 series, but it's no better than a BTS or Suncoast built 5r110, 4r100, or a Georends DCX trans.
If someone needs some dimensions I have an AT 545 lying around for another project, so I can take some measurements or pics. I also still have my service manuals from when I rebuilt Allisons.