I think a better solution would be to do what Eclipse does... it shows only a maximum number of tabs that will be legible and usable given the space available. If more open files exist than the number of tabs that can fit, it puts the additional tabs in a menu on the right side of the tab bar. Files that are inactive (not been edited in a while) end up in the menu, but will return to the tab bar when you select them. Not only is this a good UI, but it's also something that A LOT of developers already know from using Eclipse.
I agree... the tab bar in Sublime Text 2 is terrible after you get too many open files. I also typically have 20-30 open files, and if there's one thing I would fix, it would be this!!!