"DOS Memory Models" brought "QEMM" immediately to mind.

So possibly related, https://en.wikipedia.org/wiki/QEMM

I was a big fan of JEMM386, was quite revolutionary when it came out - it used only 192 bytes of memory! A godsend for some demanding DOS games back then.

And there was also HXRT from the same author, which allowed you to run win32 apps in DOS. Never really made good use of it, but thought it was still pretty cool.

386MAX user here!