I have a Dell SK-8135 USB Multimedia keyboard that I recently configured in keyTouch... overall the application works great, I just found one small annoyance:
My desktop machine has dual LCD displays and I configured each to run a seperate X server (no xinerama, twinview, or any of that). Initially after I configured keyTouch, the multimedia keys only respond when my mouse cursor is active on my second/left display (the one I had the application open on). If my mouse cursor was on the right display, it wouldn't respond.
I've confirmed keyTouch seems to "bind" to whichever particular display it was last loaded on - and this is able to be reproduced - I loaded the keyTouch on my other display (first/right), hit OK to close it, and now the multimedia keys only respond when that display is active and no longer the first. Repeating the process on the initial display reversed the behavior to the original.