I have an old 1993 IBM Model M4-1 keyboard (part# 1379590, FRU#
61G2901)that feels great to type on. It's a compact, portable
keyboard with a built-in knob (TrackPoint) mouse and no numeric
keypad. The keys are shallow; almost flat like a modern laptop
keyboard, not tall like most desktop keys. I haven't typed on a
buckling spring keyboard (like the famous Model M) in a very long
time, but I'm pretty sure that's not what this keyboard uses.
However, it's still nice and firm, and every keypress lands with a
positive "thunk". I think it might be Quiet Touch, but I'm not sure -
I thought those were mushy, and this isn't. It's also fairly loud
compared to more modern keyboards.

Bottom line is, I was wondering if anyone could enlighten me as to
what sort of key switch is used on this keyboard, and as to whether I
could find any full-sized keyboards with the same technology, past or
present.

Mark