if the right size boot is too narrow, look for another boot. if there is any pain at all, look for another boot. that being said, if the 10.5 fits, but feels snug it will be fine after it packs out.
i have a very wide foot and my northwave decades are the best boot i've ever owned. just as comfortable as my sneakers. they were just on brociety for cheap money and i just bought a second pair to use when these wear down. i freeride 90% and the decades are plenty stiff enough. i think they rate a 8 or 9 on their scale. take a look on backcountryoutlet.com they're going for 75 bucks or so.