800Mhz/512mb RAM is more than plenty to provide Gmail-like full text search for 10-20 users, while $6/user/year ($199+$1 / 20) is much lower than the equivalent cost for Google Apps Enterprise.
All that's missing is a competitive free software stack to rival the likes of Gmail/Google Docs. With the right governance, a small team of developers might enable a huge, disparate network of devices like these, with centralized security updates, a sweet admin/user UI, and be functionally competitive with most paid "low hanging fruit" cloud services (storage, docs, mail, sharing, RSS reader, ...), while offering unique features of its own (e.g. meaningful PGP e-mail, before the message leaves the building, from a web browser).
I wish someone with the right leadership skills could attract talent to a project like this. Young developers these days seem content to reinvent web frameworks and bolster Google's coffers writing crappy Android hacks, compared to those of even a decade ago, who had multitudes of successful efforts attacking Microsoft's ecosystem on its home turf.