Wider is going to be hard to come by. 31x10.5 is a pretty common/standard size. In my experience it is hard to find anything wider at that height. Not saying you can't, but it won't be easy. If you go up to 32's you can find a few 11.5's, wider than that, all I've seen are 33's.
Search the tire sites and see what you come up with. Tirerack.com and discounttires.com are a couple, but there are a zillion of 'em..
And welcome to the forum!