Jonathan...Your best bet is a 1986+Toyota rear wich is 57.5 inches wide WMS-WMS (Mazda 5.Any B2200 from 86+ has the leafs in the ideal place where the leaf spring shoes which are welded to the rear..You may have to hit the center bore on the shoes with a die grinder to make it fit. Its a 6 lug rear so you dont havt to change wheels. Axles are 30 spline and reallt tuff..I use them in my drag truck with a welded diff.They come from a variety of gears so you can play all day...(with the OEM mazda all you have is 3.90-4.62 with the rotary diff in a B2600 housing).
I have a few toyota rears if you need one..i even have one with 3.42's ..great for a V8 swap. I have a few machined axles with a 5 lug setup and supra & rx7 disk brakes.
Jonathanrotaryiz@hotmail.com