It seems like an iPhone 3G(S)ish prototype, given the smooth back and lack of a front-facing camera.
Note that it has no home button at all, so I think it’s an earlier version of the above design.
No Apple logo either.
I am tripping balls over the old icon set.
It’s really fat like an iPod classic, indicating it’s got a hard drive, but the front is all-touchscreen. Kinda gross looking, if you ask me.
All in all, combined with the insight about the iPhone 4’s original design inspiration and the decade-old iPad prototype, this week has provided one of the most revealing looks ever into Apple’s design and prototyping processes — it’s a real peek behind the curtain. All of these designs are very good — well, except for the iPod touch — but none of them were good enough for Apple.