Well I would certainly love to see both! (but I understand the predicament)
Not quite exactly your same situation (this person did promise from the get go to share then never did) but you might see some of the reactions in
Zimbra 4.5.6 Open Source Synchronization - It works now ! (might be why people have laid low on replying to this)
On a lighter note there are 2 very active threads in it's place:
http://www.zimbra.com/forums/zimbra-...4j-code-2.html &
Open Source Mobile Synchronisation