Least PC-Compatible MS-DOS machines?

One that I remember - heck, I actually have a system buried somewhere - was the FTS Series 86. The FTS-88 was a typical 1980-ish CP/M-86 machine running on an 8088 (although I have an 8086 processor card for it), built in monitor, separate 8-inch disk drives that were always going wrong. The replacement machine was the FTS-86. An 8086 machine in a more typical early '80s case with two built in 5.25 inch diskettes and a separate monitor. This ran a CP/M derivative called "Concurrent DOS". Can't remember who provided it. The machine was billed as the "non-compatible compatible". What I do remember is that I brought home some disks from work (I was a student on placement at IBM when my father got the FTS 86) and tried running Lotus 1-2-3. It ran, even to plotting graphs as though it was on an IBM with a Hercules card. We were impressed! Honeywell bought FTS at around that time. They went on making the machine, but gave it a different name. Microsystem Executive, or some such meaningless sobriquet. Philip.