Thanks for the kudos guys -- I'm glad to have contributed something to the Holy Hack.
BFMersion: I, as well as a few other people, jumpered every combination on the matrix and didn't find an ESC keycode either. It still could be possible with a hardware mod to the keyboard encoder chip, but even if it were, most people could not do the mod as it almost surely requires cutting traces, lifting pins or adding resistors.
On a related note, I'm getting close to globally remapping the backquote key to ESC so that it will work in the BIOS setup screens and won't require any TSR program. The required patch to the BIOS was trivial to determine, however I still need figure out what checksums in the BIOS need to be tweeked to accomodate the patch. There is damn little on the net concerning this info!
BTW, that 2k TSR program was written in Microsoft Basic using the PDQ library from Crescent Software.