I don't know what your frame looks like ( if it's boxed or open),If it's open you could use just about any crossmember that would fit. An example; an 80/early90 crown vic is tubular and you cut to fit, smash the ends flat and drill a mounting hole.

As for the rear end you have to measure from the wheel mounting flange to the other side mounting flange. That is the width you need. Sometimes you can go a little wider or a little short, just have to measure what you vehicle has room for.
Some of the s10 blazers had 6 bolt rears you may check for one of those.

Tommy
59 apache 1/2t
261 short stepside