There's a new source of grass fed beef in Phoenix. It's called OX Ranch (somewhere near Wickenburg). Their web site is www.azgrassfed.com. I have not purchased any there, but I fully approve of their methods. They offer beef with or without hormones, so take your pick. They keep their animals on grass their entire lives, so you won't lose any omega-3s due to a corn-fed diet.
The price is not bad either when you compare to what most places charge for grass fed. They say on a typical order, you pay an average of $5.60 per pound - averaged over all the steaks, rounds, and ground beef. My only concern is the amount you have to buy, but if you find one or two others who want to share, then no big deal. They even help you find someone to share with.
Oh yeah, you also get to spend a day at the ranch fishing, hiking, and boating if you're a customer. Never seen something like THAT before.
Hope that helps.