With Ubuntu apparently planning to release a version aimed at the ARM platform and with a couple of 2nd and 3rd tier manufacturers working on low-cost (~$200) netbooks with long battery life this sub-group of devices just might become viable.

Something resembling the ($900+ !!) Vaio P (ie. with decently wide keyboard and screen) would make for a very portable system although well-built "traditional" netbook format would also be fine.

Next summer looks to be interesting time.