This is an old post, preserved for reference.
The products and services mentioned within are no longer available.
I've recently got my hands on an IBM XT model 5160. This is the successor to the original IBM PC 5150. It was compatible with it's predecessor, so is probably one of the first to call itself 'PC Compatible'.
That's enough for Part 1. In Part 2, I'll go through the drives and the case and put it all back together.
2022 Update: I really must get around to putting this back together!