No, I don't. And in fact I suspect that IronMaiden isn't the target, or it would show on the bug page, as it does for some other bugs.
In both the bug and on the forum I've argued against devoting resources to Outlook 2011 support. Not that it wouldn't be nice, but it just seems like a lot of effort to implement a proprietary protocol, when standards like CalDAV, CardDAV, and IMAP are available. I'm not affiliated with Zimbra in any way other than as a customer, but it's possible Zimbra has a similar view to mine.
Ultimately though, it's not my opinion that counts--it's whether people will decide to buy/use Zimbra based on that feature. So you should vote on the bug if this is something you want, and if you're a (potential) customer, you should mention it to your sales representative.
Purely as speculation, there might be some ways that Outlook 2011 could be integrated with Zimbra without fully implementing Exchange Web Services at the server--basically, using an iSync connector. But there are three problems with that. First, I don't know how much work that would be. Second,
Zimbra seems to want to get out of the iSync business (although that doesn't preclude third parties continuing work). Third, iSync is no good for realtime lookup of free-busy information.