I'm just going to point one more thing out. I was on a winter snow trail ride a few years back with a bunch of different types of vehicles...I was on 31" BFG ATs. Couple were on 35s, MTR and Dunlop Mudders. A bunch were on 33's, all mudders of different types. There was a tacoma on ATs as well. Most of the rigs were TJs.
Dunlop guy was "breaking trail" and got stuck, keeping everyone behind him up. Including me. He kept getting pulled back so he could try again...got stuck repeatedly. I got tired of this so I hopped up on to the side of the trail (fairly wide brushy frozen trail for all the greenies...I didn't damage anything) and cruised up to the head of the line, pulled in front of him, and blazed trail until we hit a steep hill when the trailboss told me to hang back.
Trailboss = dunlops. Nobody else out there was able to bounce off the trail and bypass anything, or they didn't try. My ATs, in 10.5 wide, showed up pretty much everyone else that day. So it's not just about size, it's about the right tire for the job when it comes to tread pattern, size, and the driver's ability to make it all work. Dunlops = not the right tire for snow. Or really anything else for that matter.
But when it comes to 10.5 to 12.5, I don't really think it's nearly as important as tread design. I believe that the skinny vs. fat tire debate should be kept between two groups of widths, from 9 to 12" wide (commonly available), and "wide" sizes are 13" or wider (not so common).
I'm personally planning on 16" wide 40s, be it LTBs or Pitbull Rockers. Either way, they're going to make winter wheeling so damn easy for me.