I think 11.1 is where it will go. You need a floor speaker in each corner, two side centres, a front centre and four ceiling speakers in each corner of the room - otherwise you get the feel of the correct height as a plane lifts off.
So it's got to be 11.1 for realism.
I know some folk will say I'm wrong as I've forgotten the upper and lower front centre re-enforcement speakers and the rear centre, but I think that's overkill unless you have a big room, of course.
Now where did I put my shares for those speaker and speaker cable companies.