Just guessing, since I don't do PIP. What about a layout choice, then a hotkey entry item.
(1 1 window
(2 2 windows
(3 4 windows
(they are just used for the size of the windows)
Make them graphics grab objects. You have 8 blank spaces (layouts) that you can drag the objects to.

Each blank spot (layout) would be a window that is like the mouseover option. It would let you layout the windows like you would like. Sorta like a drag and drop layout system. Also you can select the tiny windows and name them if you want so you could always put your tank/healer in a specific spot (which is what I thought the person was asking for).

Then below each blank space, you can select a hotkey button, that you type in your hotkey to select that look. So if you selected 1 in the first blank space and put in SHIFT-A, it would make the layout you selected happen.