I agree with the Linux running on a MBP part... indeed, I'm planning to do so when I buy my MBP in a few months. However, I do recognize that I'm not the typical use case for a person using this device, spending most of my time in the command line, etc. For actually developing something, there's a much better ecosystem running linux.

On the other hand, I'd take iOS running on, say, the Galaxy Nexus. If I jailbreak iOS, I can easily run iSSH, install inetutils, vim, etc, and come halfway to an amazing development device with access to the whole app ecosystem. For me, that's the dealbreaker (or maker, depending on the perspective.)