I'll look at those first two, but straightline performance just turns up an atv shop. I took a 2nd look at 5-speeds for a bodies, and indeed some guys on here are adapting the trannys from the 90s dakotas
The NV3500 comes from the V8 94-04 dakotas, the year they had the 5.9L, so that'd be an option (although both look like they require some fab work to make fit).