A little off topic, but Mike - have you ever looked at PostPath (recently acquired by Cisco)?
The last implementation I did involved 4 standard Microsoft DC's, but all the mailboxes were stored on PP servers. The organisation had 50,000+ users and slashed their CAL bill by 65%. None of the clients know any different, and mailbox backup was simplified enormously.
Just a thought if you wanted to double your profit margin.
Interesting - cheers for that!
Currently we virtualise our Exchange servers anyway, so backup is done per VM rather than per mailbox, but if it behaves in a mailbox-transparent way as Exchange then i'd be interested, as there's a few quirks that make Exchange not 100% ideal for a hosted platform (but we get around them and it's stable and reliable). I just hope Cisco haven't ripped the heart out of the package (or the licensing) already!