I might be blind, but I couldnt find this on the " My Dashboard" page. I feel there should be a link to start a new thread on that page? (unless it isn't there already)
Drop down is a good idea. Or you could have them all listed and have radio buttons next to them, so the user would have to click on one of them to proceed to create a new thread.
It's still on the list :( We are backed up working on a site-wide redesign, which is blocking all new features. But it will be worth it! It's gonna be AWESOME! It just might be a few more months :p