I think Chrome OS + hardware is a fine idea, but can't see it succeeding commercially. You need buy in from corporate IT to gain any kind of marketshare, and corporate IT really like product support and life cycles, two things that Google is not known for.

Because they get so much money from their search and ad revenue, Google can afford to go out on a limb with this kind of product. Time will tell if they're sawing the limb off while they sit on the wrong side...