I believe ezboard had an option like this. Here is a screenshot of what I think you guys mean. This would be a pretty sweet hack. It would make it just a little easier to move stuff, BUT, it's not like it's TOO hard already. Remember, these people who makes hacks aren't getting paid, so generally if a hack requires some serious work, which I believe this one would, you have to understand that usually the only was it's going to ever be made, is if:
1. Somebody who knows how to do it likes the idea and wants it for their own forum, so they hack it AND release it...
2. You pay someone to do it for you.
Just my two cents

This hack would be cool though.
Here is my screenshot of this idea: