I'm currently using david the deity of accelloration's wonderful Xgl ;) After
the plug thats rightly so after my bag and cap (RE: rev. Ted) arrived, novell
novell novell, novell novell novell ;)

Anyway, I see edge_flip_dnd, edge_flip_move and edge_flip_pointer, why don't I
see corner_flip_* too, it makes more sense to have corner flipping (RF: fitts
law) than the edge, as the edge is infinite in the compiz cube it gives you
nothing to aim for. A corner would serve to guide the cursor to a point of
action, and also the corner is a place where miss hitting the edge can cause a
strange sort of motion sickness as its kinda bouncy, you're not expecting it and
it feels very accidental, not so much so with dragging and moving but with
pointer definately. 

I think corner flipping would be much more appropriate with the mouse pointer.
In fact I actually use this now with brightside and a dodgy hack;  

xte "keydown Control_L" "keydown Alt_L" "keydown Right" "keyup Right" "keyup
Alt_L" "keyup Control_L"

It would be more suitable to have this in compiz as an option.