I'm now confident, having figured out how to use both AllInOne and AutoHotkeys, that either one of these programs can be used to set up a two-key-combo-quit-emulator function as described in my initial post.
For example, see my last post here describing how I got AllInOne to work with Daphne:
http://forum.arcadecontrols.com/index.php?topic=120183.0I used AutoHotKeys for Demul with success as well.
I used Mala Hot Keys to quit Sega Model 2.
If you want to remap a single key to the quit emulator function and the emulator itself doesn't allow a remap (best option if possible), then HotKeys within Mala will do it just fine. Mala Hotkeys will also map a two-key Close (Quit emulator) function as long as one of those two keys is Shift, Alt, or Ctrl.
Mala Hot Keys set up for this is as follows:
Name: Close
Type: Post
Source: (1st chosen key)
Destination: ESC (if the Escape key is your emulator's quit function)
Then just check "Shift", "Alt", and/or "Ctrl" to create the 2+ button combo to quit the emulator. Again, this works great as long as you are OK with using Shift, Alt and/or Ctrl as the 2nd or more combo button. In my case I didn't want to use any of those keystrokes as the second part of the combo. Enter Auto Hot Key or AllInOne.