I don't use roll-up too often - but what I would love to see in it's place (or in addition) is this:

1) I set up a folder portal

2) I set it to a small size (like 8 - 10 documents showing).  I set up like 6 more in a tile like formation.

3) I double click on title bar of any one of these small windows and it goes the full vertical length of the screen.  Then when I'm done - I simply double click again to return it to it's original small size. 

This way I can have a bunch of small windows with my various folder portal files visible but I can quickly expand one of them to the full length of the screen.

Just a suggestion