AA battery powered mp3 player?

How about an mp3 player that uses a Motorola BR50 battery? That battery is 710 mah and 3.7 v. A Player around the size of the Clip+ that uses an easily swappable(not soldered in) BR50 battery. The BR50 has over double the power of the battery in the Clip+. Imagine a Clip+ sized player(or just a tiny bit larger) that gets 32 hours of battery life, and for which the battery is easily swappable and someone can carry spare batteries. A BR50 battery is only around $7 retail on the net.