Howdy, Neighbor! Small world! We're in BA too, although I usually claim Tulsa since more folks are familiar with that name.
Well, let's see... Saturday I went looking for just such a thing, and found a fantastic oriental market instead that DOES also cater quite a bit to the Mexican community. Go to the intersection of 21st and Garnett, to the northwest corner of the intersection. A little north of the intersection you'll see a market called "Nam Hai". They may have what you're looking for, plus a WHOLE LOT MORE.
After you go there, then come back across the street south to the southwest corner of 21st and Garnett, a bit south of the intersection, to the Mercado. When you go in the front door, there are some flea market type booths off to your left, but there is a restaurant, a meat market, and a small grocery all within this big building off to your right. Don't waste your time on the chorizo, and be sure to check out the HUGE fried pig skin / pork rind / whatever laying up on top of the cases of the meat market.
That's all I had time to check out that afternoon; I know that there are some other Mexican markets in the general vicinity of 21st and Mingo to 21st and Garnett, but I don't have details yet - the search still continues. If you'll send me your e-mail address, I'll keep you updated. After a recent trip through New Mexico, I'm on the search for tubs frozen chopped roasted green chiles, to no avail yet. I guess I'll have to learn to roast them myself.
Keri C, smokin' on Tulsa Time, but actually located in Broken Arrow.
keri at gbronline dot com