Rustylugnut, ever been to the diyelectriccar.com website ? Also,try car-part.com for used car parts. Larger Kwh Tesla batteries can be had for around $10,000.00 and maybe even a Tesla rear mounted motor-controller. If you have talented friends I can't see a conversion costing over $30,000.00 and that may be high.
Weight of trailer and load will need careful scrutiny. Still believe 150 mile range loaded is possible. Do more searching. Good luck if you try this.
UDATE: You are in EV parts heaven. No shipping required, possibly. Tesla 75 Kwh 600+HP motor at this location for under $3000.00.
https://hsrmotors.com/products/driveunits