We don't have it already? That's about the most important IMAP feature on a resource limited device, and should be implemented by all decent mobile e-mails clients (I'm looking at you too, Pocket Outlook). Scheduled syncs (every x minutes) waste battery life, and manual syncs mean you don't know when you get new mail - I gave both up and hacked together a SMS push system to force manual syncs when the mailbox changes on my Touch Pro, but it's still ugly. I was really hoping to get away from something like that.