Not sure but those blokes in the 666 room a few years back had some discussion on this very subject.
We had one of these once
http://www.ebay.com/itm/Waterproof-Underwater-Mini-4GB-4G-Swimming-Water-Sport-MP3-WMA-Player-FM-Radio-/290721623241?pt=LH_DefaultDomain_0&var=&hash=item43b05becc9#ht_3841wt_1156And it was rubbish. Pain the neck and waste of good old hard earned cashola.
I reckon if you found something decent that worked you could just retro-fit your wettie - maybe make a little pouch on the back of it up by your shoulders and stick it in there.
Personally I enjoy the piece and quiet when out surfing

But have also thought about it on more than one occasion.