Bluetooth DOES work underwater. G-Shock, the watch brand by Casio, makes a Bluetooth watch. There's a video that this guy is swimming underwater, and when he got a text, it showed up on the watch.
I wonder how much progress pro2a has made so far. If his build seems to work out without too much problems, I might attempt the same with my soon to be replaced socket 775 motherboard and Pentium D processor.