I know this thread is old, but I have the same problem in MoCo. I just drove down to the Restaraunt Depot in Capital Heights to pick one up.
Last night I spent over two hours driving around to visit 8 different stores...and all I found were a couple over priced flats. I haven't missed Texas this much since SB 281 passed in April! I went to a few chains, a Costco, an organic grocery store, a so called "meat and fish market", two Korean/international grocery stores and nothin'!
I think I paid 2.69/pound at RD for USDA choice. There is P&F in Landover that sells choice for 3/pound, but their hours aren't very convenient. I know a great butcher down in Bryans Road, but that's a hike. The Walmart in Fredrick had a decent selection a couple weeks ago. But I know they don't stock them year round.