Abhi Do you think a forum is suitable for a support system ?
Yes, these days with improved permission system, it is possible.
Abhi something very similar to a ticket based system ?
Not as good as a ticket system. I think a ticket system is easy to maintain and simple.
Abhi providing official support without actually compromising customer privacy ?
Yes, a lot of product support people do that. All they need to give away is a public user name. Everything else can be private if you tweak the board well.