Automatically choose item if unambiguous

I would appreciate an option so command-t would automatically select the last option available. This would be especially useful in the buffer switcher as i don't have that many ambiguous items and that would speed up my switching.

otherwise I am loving command-t :)

Thanks in advance, Jonas

P.S on another issue, is it possible to make the command-t window eat away from the window above it, so it doesn't push up the text lines when opened ?