So one of the more well known moders over at modretro.com by the name of techknott has made something interesting... a PS2 portable... why you might ask? Well besides it's obvious cool factor, he built this for someone and they never paid up. so it's up for sale on those forums. I don't know if that means you or I could buy it, it may just be for there user but still very cool
it comes with
PSone screen, orig back light
usb
headphones
on board sound
NO BATTERY (he said that was done for cost reasons)
so i you want to buy this bad boy head over there and see if you could swing a deal and check out his vid below
http://www.youtube.com/watch?feature=player_embedded&v=jU9nF7noYYU