I didn't know about this until just now, but it seems that someone has beat Logan to the punch with a portable music player that can accept ssds. It uses msata, so no hdds. That isn't too much of a problem though seeing as how an hdd would increase the electricity use, increase the noise it makes, increase the heat output, make it easier to break, and you would have to deal with weird physics while it was powered up (the spinning platters in an hdd make it feel weird in the hand, like it is fighting you; physics 101 anyone?). Anyway, here it is in case anyone is interested. I know that Logan talked about making one at some point, or at least a 2.5" hdd version of something like this, and I would guess that he was aiming at a lower price point.
http://www.aurender.com/product_v1000.php