"Pop up" bars

[Daemion Immolatus]

Is there an addon that allows for having bars pop up on mouseover (or click) on a button?

I want to be able to hover over a button (or right click) and then display various casting options, like a menu that expands. It should be similar to the functionality as it is found in the 'sphere' type addons where you can expand one button and then see multiple casting options.
I would like to know if something like that is possible from the toolbars as I don't really like the 'sphere' type addons.