GUI layers
 

It would be great if GUIs (which are always layer 11) could use layers 11-20 or something like that. It's a pain to deal with complex interfaces using GUIs because things are always getting pushed in front once focus shifts to them via click. GUIs on a higher layer would always display above GUIs on a lower layer. GUIs on the same layer would work as they do now.

YES.
This is constantly annoying me on Sin City with other people's GUI scripts showing on top of the HUD and whatnot.