I'm not sure if this solves your problem, because I'm still on a non-TB Mac, but you can use CMD + [first letter] to select dialog options. For example, if you're closing an app and are asked if you want to save an open file, the dialog might have "Yes" preselected, but also let you choose "Don't save". If you hit CMD + D it will choose the "Don't save" option. Same thing for something that might say "All files" you can hit CMD + A to select it.