I know you mentioned mail order.... but I used eatwild.com (recommended on this forum a few years ago) and found T.O. Cattle Co. in San Juan Bautista, CA (aka Morris Grass Fed Beef), it's a family operation. Once a year when the meat is ready, Joe Morris loads up boxes of nicely packaged beef in a freezer truck and delivers to various locations in the San Francisco Bay Area. The first year I bought a split 1/2 (1/4 of a cow) just to see what is was like and the last 3 years I've bought a 1/2 share. It's about $6.50/lb + $25 delivery charge, I store most of it in our small garage freezer with the rest in the indoor freezer. I always order extra marrow bones for stock!
I really like that I have grass fed beef always available in my freezer ( well, most of the year, it lasts our family of 4 about 9 months).