Whoa! That's pretty slick! If you can't see the video, let me describe it -- a fellow from the Chinese forum ePrice is using a paired Bluetooth headset as a remote camera button on his HTC One X. Not all headsets will work (and unfortunately my Motorola headset falls into that not-working category), and the button combination needed seems to vary a little bit, but this seems to be an undocumented feature with the One series phones. Give it a shot, and holler in the comments if your headset works -- 'cause I need a new one now.
Source: ePrice (Chinese). Thanks, anon!