I would think you could find a 6 lug 14 bolt semi float somewhere in your neck of the woods. I put one in my 1993 Suburban. Mine came with 3.73 gears so I just bolted it in, even used the old 10 bolt parking brake cables. Needs a conversion U joint or a 3/4 ton driveshaft.
They come out of 88-98 Chevy or GMC pickups with the F44 option I believe. Mine came out of a K2500 light duty extra cab short bed, 3/4 ton springs and torsion bars and the 6 lug 14 bolt rear axle.
I have seen K1500 trucks with this axle though.
This way you can swap out all 1500 front and rear differentials from the wrecking yard to match, probably cheaper than gears.