More Clarification (Score 1)

I realize I should have included all the relevant data in the initial question.

What I have done:

I used 'xev' to see if any events were generated for the extra keys. Only the MickeySoft keys generated any events. From my (admittedly limited) knowledge of the X event system, if the keyboard handler isn't generating a key pressed event, then nothing I do with xmodmap or xkeycaps is going to help. I first have to convince the X server's keyboard code to generate some kind of events for key presses of those keys.

Once that part is done, I'm fairly confident that I can deal with xkeycaps/xmodmap to make the keys actually useful (and yes, I intend to try to create the stuff for xkeycaps so others can use it later).

I suppose I'm a bit confused as to why X has to have it's own code to do hardware scancode conversion to software events, when (at least under linux) this seems like a kernel thing to do. I have my linux kernel being very happy about the extra keys, but X seems to just quietly ignore them. I fear I'll have to delve into the XKB extensions to get it to work.

Thanks for all the comments so far folx.