I'm going for something like this, from the blog of D. Comeau Custom Knives (many thanks for the helpful post!):
So far I've cut and welded the square tubing for the frame, and had some expert assistance from Yulianopolis drilling the holes in the baseplate for the motor mount:
Next steps are welding the frame to the baseplate, and then working on mounting the tracking wheel and tension arm. I'm pleased with my progress so far:
Test-fitting the tension arm and belt:
Finished the platen and work rest:
The finished product: