Naturally, we have different stores here (Randalls, HEB, Albertsons); I think if one of the stores would start carrying a small sampling they would find it profitable, and drive business for other items into their stores. As an example, the price for imported frozen halal turkey can top $3US per pound!
It should be made clear that, while most Muslims would consider Kosher as halal, the opposite is not true: halal is not necessarily Kosher. Halal provisions do not require the separation of meat and dairy, and shellfish is halal but not Kosher.
Now lets through some fog onto the roadway just for fun: “halal” is probably not the best word, as it is a bit general. “Zabeeya” (pardon the clumsy transliteration) loosely means slaughtered according to Islamic law, and is what most Muslims are really after when they visit a halal meat shop.
There are two camps (at least in the U.S.) today, and neither is clearly right or wrong (IMHO). One camp will eat meat from “the People of the Book”, meaning both Jews and Christians, arguing that the Qur’an clearly says it is OK. This group has no problem with eating a Big Mac, so long as it is bacon-free.
The other camp says that yes, the Qur’an does make lawful the food from “the People of the Book”, but that Christians in particular no longer slaughter their animals in the same manner nor in the name of God as they did 1400 years ago. Ergo, since their slaughtering practice is no longer similar to that of Muslims and Jews, their meat (well, the meat of their animals) is no longer zabeeya, and hence no longer halal.
My WWWAG is that 30% of Muslims will refuse any meat that is not zabeeya or Kosher; 50% eat zabeeya when available, but will eat non-zabeeya meat as long as it is not haraam (pork, leopard); and 20% don’t really pay all that much attention.