I'm pretty sure you would not need a medium format digital camera to make very good copies of 10"x10" prints. Just about any full-frame or APS-C format digital camera should be adequate, with the right lens and lighting.
My few attempts to photograph prints using my digital camera were frustrating due to reflections. Even with polarizing filters over both lights, and one on the camera, I found it to be very difficult to eliminate all reflections. I was fighting cheap lights and a home-made copy station due to buget limitations. Maybe with a proper copy stand and quality lights, it would have been easier?
So for me, I'd try a flatbed scanner first.
I do use a 16MP digital camera (APS-C) to copy my negatives. When copying my square negatives (120 format), I take two overlapping images and join them into one using Lightroom/Photoshop; works great for me. I have not tried to stitch overlapping images from my flatbed. scanner, but I would expect that to work, as well.
What software do have available for post-processing digital images? Check to see if it has some sort of "merge to panorama" feature.