Sony's P-Series failed to live up to its expectations rather spectacularly; combining highly desirable hardware with a less than desirable user experience. Luckily, that may be set to change.
A Sony rep speaking to Tech Rader at the W series launch let slip that the oh-so-expensive please-don't-call-it-a-netbook will see an arguably needed update this October or November. Among the improvements, faster boot times are, apparently, to be featured.
Given that timeframe it seems impossible that Sony would fail to at least offer Windows 7 on the revised P-Series, and our experience with the Release Candidates to date suggests that swift decent boot times are one of the benefits 7 has to offer. Not to mention Microsoft has designed Windows 7 with the lower performance of netbooks in mind, so generally speed should be better than Vista.
It's also possible that Sony will offer newer Atom processors on a revised P-Series. Faster clock speeds and improved graphics grunt wouldn't go amiss given the crazy price tag - although don't expect Ion to fit into the P-Series chassis any time soon.
Of course it's always possible that Sony will be giving the P-Series a speed boost in an entirely uninteresting way making the system no more attractive then it is now. I sincerely hope not, though.