Change the default IMAP Inbox folder on Mail.app Ever since I started using Priority Inbox in Gmail I don't really care about my main INBOX folder on Mail.app. Is it possible to change the default INBOX folder to [Gmail]/Important?
This is a very old tip but I can confirm it works. There is also some useful information in the comments section with regards to this.

Forcing the default mailbox in Mail

Apart from this hack there is no other way to do this. I am assuming the global inbox functionality is the reason not allowing you to change it.