Grass fed beef is only good if you choose leaner cuts of meat like you stated above. If possible, find organic grain fed beef. Grass fed beef has a rather mild flavor; unless a less beefy beef is what you are looking for. Google search and you can find beef from Montana from Scottish Highland Cows.
See my query under:
Grass fed beef - wow!!! Where to find it in OC? Any local farms?
I had some fantastic brisket in San Francisco at the Ferry Terminal Building at Boulette's Larder, and wondered the same thing. Evidently not in the OC; but you can order from places in Northern California. Let me know how your search turns out.