Shelbot? Surely you jest. I think many have done exactly that as it is not that bad to do. Especially if you do not have the engine stand or the hoist to pull the parts out of the engine bay.
I did mine, ring replacement only, in the car. But I didn't have cylinders out of spec or round. I did have rings that were worn, broken and stuck in the grooves and blowby in two cylinders. I measured the compression first and two were near new and the others we like 240-220 psi. So way off between them and starting in the summer was getting to be a glow plug only affair.
You are looking at the right place for parts and the right ones to put in there, You should determine if the cylinders need boring to make them a circle instead of an oval. Good machine shop can measure them up with proper tools if you don't have them.
I did it just a few months ago and they didn't even charge me. I thanked the foreman for the work and asked if I could give the guy that did the work a tip. He was surprised I asked but was like sure, go ahead, and smiled at me for the gratitude I guess. The kid was speechless and even looked to the boss who gave him the yeah, take it sign. It was cheaper than buying the tools. And the kid and I had a good discussion on engine rebuilding while he measured them top and bottom.