I agree the companion device concept is likely inevitable -- it looks like it just won't come from Palm
People who have used the Foleo said that it had serious shortcomings as a light and simple laptop. It was apparently underpowered and the Palm notion that it was a peripheral first and a network connected computer second, was odd, if nothing else.
However, the little time I had to play with a prototype device earlier this year was enough to underscore the potential of a disk-less portable. Indeed, if Palm doesn’t build it, someone else is certain to. There are just too many Web services that require no more local computing than what is necessary to run a Web browser popping up all over — even from Microsoft.