If you're willing to spend a few extra dollars, why not keep it even more local and support the local ranchers?
As I mentioned in the other thread, I buy my meat directly from a local farmer, Joe Rush. The cows are grass-fed, pastured, yadda, yadda, yadda. He also does pork, turkeys, chickens, lambs, and ducks. Joe has never tried to run me over when I meet him in Squirrel Hill with my delivery.
You may also want to look into Penn's Corner Farm Alliance--they work with other local producers and have both beef and chicken shares. Neil Stauffer (the manager) could help you find a good local supplier, too.
And of course, they aren't know for it, but the East End Food Coop carries a pretty good supply of local and non-local, sustainable raised meat. They don't have the same sort of selection as a butcher might, but it's really not bad, either.