nice i wanted to make the same but a few things held me back
1 canabalizing the working headset could cause problems if the stereo wiring in the xda headset were poor quality and i could end up having to listen to music in the bus played by the normal speaker on the xda adding to the enjoyment of the rest of the pasangers :P
2 if the length of the mic and buttons had to be near my mouth the length of rest added headset would be added making me look like a d00d who were a bit too much into rubber :P and of cause the added lenght could cause music quality loss not that i would notice with the music i listen to :P
hhhmm ok i may be a jerk but i'm a jedi jerk like my father was before me
BTW "I can't use a skeleton arm with that"