Screen Used PADD on eBay
My buddy Steve Hamedl has a Star Trek PADD purchased from Screen Used Props and he is looking to sell it. I can vouch for both Steve (heck, the guy is in law enforcement!) and Screen Used Props, which is a top notch seller of authentic props. I actually purchased a screen used Star Trek Voyager "Relativity" Tricorder from them, the only Star Trek prop I have bought that wasn't from Christie's or IAW, so you know I trust them!
Steve has the PADD on eBay, so check it out if you are interested in one.
Alec