Thanks guys for keeping this alive. Our build team is working on a few things at the moment getting out 4.5.X patches and working on the various 5.0 betas. Thanks for your patience and as mention a few times the best way to get this as an official port is show interest to purchase zimbra. A simple email with you and your company's contact info and the number of seats will do.
sales@zimbra.com keeps a list of these which we use to evaluate new platforms periodically.
Many of us at Zimbra (including myself) came from 100% past. So it's not new to us. Just haven't seen the commercial interest yet to move to a supported option. Unlike adding a new linux distro which we can run on VM's and our same hardware at least for a Sparc based port it'd be a healthy hardware investment for Dev/QA/Support/Sales Eng.