This might be a bit silly idea. How about one more button for those moments when you are for example mixing and using the ol' technique that requires you to balance tracks so that you first select one track as a solo track then you select another as a solo track and balance them until you have many tracks selected as solo tracks but then you suddenly want to hear only one of the solo tracks. This 'super solo button' would make it possible to listen only one or more of those tracks that are selected as solo tracks so you wouldn't have to put all the selected solo tracks as normal tracks and then select that one or more trackd as a solo track and then later again select all the needed tracks as solo tracks. This would be a time saver IMO. The more tracks there are the better it would be to have this kind of button.

Good one. I'd probably want to call it sub-solo rather than super-solo though.
 

Make a read on Exclusive Solo in control bar.
 
As I read you post I think it's close to what you ask for.

Ok I did not realize there was that. Now I know and will use that function. Thanks for the comments.