Dude-
I'm sorry to tell you this, but you're pretty much toast. install.sh -u does in fact remove everything. Even Mike's method won't work, as you don't have the message store.
The best hope you have is to take a look at the account db structure and try to export it, then import it. You'll need to try and dump the dbs to sql files, then reinject them. . .but that is further than a long shot.
I've never done it so I don't have any advice for ya. This wiki article might be able to provide more information:
Account mailbox database structure - Zimbra :: Wiki
the zmprov commands won't work, but it gives you an idea with how we store the data.
That's about the best I can do.
Good luck,
jh