In case you don't think there are enough PMPs out in the world, then here's another one that might suit your fancy. It's called the Shiro SQ-S and it actually offers something a little bit different than the norm. In fact, you can charge up this PMP with solar energy.
This PMP doesn't require a wired charging method in order to get it going. That really places it at an advantage, because how many times have you found yourself out and about, only to have your music player run out of battery? It does take six hours to completely charge the device however, and that's with "full sun." Even so, you could always plug it into the USB port of your computer and charge it in 4 hours, instead.
Even so, I could see how if you're out without any means of charging a device this would come in handy. A full charge makes for up to 38 hours of audio and 10 hours of video playback time. There isn't a price tag or any availability information just yet, but we'll keep you posted.