Sign me up. Thus far I've just been using a Big Arsed Battery Bank on a short cable in my back pocket. That plus the Frame's built in battery nets me something like five hours of battery life before I need to return to reality. Inconvenience aside, I do like the battery bank itself being a commodity rather that proprietary component. The PRC will happily sell me another one any time I like, surely even long after the Steam Frame's own discontinuation.
The Frame's stock audio solution is perfectly acceptable except since the drivers are so far from your ears it's rather loud to other people in the room. I imagine this puts a damper on some users'... activities. For me, it mostly just annoys my spouse who has to listen to me shooting zombies or whatever else all afternoon.