Craig, I think you're nuts
Okay, not really. I think Craig is a really smart, nice person. But I could not pass that up.
My room is nearly identical in layout to the one being discussed. I have M60's and must say that the imaging and soundstage is really superb. I always wanted towers, and avoided many angst-ridden "what if" moments by getting the M60 instead of the M22, M40 or M50.
I do think that the M80's would be WAY overkill for that room. The M22 would be a wonderful choice; I think Craig is right. But I also think you could have a very satisfying experience with the M60 in that space. I sure do.
With the room 12' deep, if the couch is on the wall, you should still have 8' between the speakers and your ears. I'd say go for it!