Feature: syncing calendars from multiple Gmail accounts?

[Bones]

Wondered if this was ever considered as a possible feature: the
ability to sync calendars, contacts, etc from multiple Gmail accounts.

With more and more people migrating their small businesses, groups,
and whatnot to Google Apps (Gmail for personalized domain names) the
possibility of having 2 or more Gmail accounts is common. It would be
great if I could sync calendars (at least) between multiple Gmail
accounts.

Thoughts?

[Adam]

Yes, I have the same question. I've got 4 Google Apps accounts
because I've got 4 different ventures going and didn't want to
commingle the e-mails into 1 account. But I would like to ensure that
any changes I make to Address Book get propagated to my Google
contacts list in all 4 Apps accounts. Is this possible with Spanning
Sync? I would buy it for sure if it was possible.