You sure? It certainly looked like a mini version of iOS in the keynote.
Yes, it does
look like a mini version of iOS. That's what they were going for. It's not though, it's still custom iPod firmware, just made to look like the rest of the product line.
However, I don't think that this will bar anyone from hacking it. It may not be jailbreaking, per se, but as someone pointed out, all older iPods are vulnerable to hacking as well. In fact, hacking Apple devices has always been common, it just didn't become well known (or practiced) until people started hacking the iPhone, probably because of all the amazing things the iPhone has (gps, mic, camera, accelerometer, multitouch, etc.) that the iPods never had. You could hack an iPod, but then what? There was very little interest for developers to make 3rd party unofficial iPod apps. Just games mostly. Maybe a few other tweaks, but that was it.
The new iPod nano will be hacked in due time. The real question is whether or not developers can make any clever/useful/amazing apps for it. There is no official SDK, so developers will have to use a toolchain to compile apps like we did in the old days of iOS 1.x (before the app store). It's not impossible, just more difficult. I wait with anticipation to see what will come up.
