Seen in a video on YouTube, a rather interesting EVT iPad.
On the back, you can see a sticker, a marking with the serial number of this specific model, and a sort of frame around the Apple logo. According to DongleBookPro, this is a kind of QR code used to identify the prototype. On the front, the prototype’s serial number is printed on the bezel. The iPad does not have a second dock connector, but it is a cellular model. It boots with a (mostly) modern version of iOS, but with a startup message and verbose mode, meaning some command-line information appears before the UI loads.
Internally, you can see that the first-generation iPad looks quite empty compared to modern models, but once again, there are traces of the second dock connector.
The iOS 5 version used here includes a fair number of settings and apps, and I’ve included some screenshots. You can also see several test applications, especially for Game Center.

As always, you can check out the video. I’m not embedding it since videos sometimes disappear unexpectedly…