Gluten content of regular beer... this is the one thing on the internet that is damn near impossible to find! This is what I have found out so far-
Both Estalla Damm Daura and Widmer's Omission are brewed with barley, and have the gluten removed to fall below the 20 ppm limit that is considered gluten free for food (but not beer).
Heineken has also made the claim on their website that their beer falls below this limit.
On another one of these old "gluten content of beer" threads on Chowhound, someone named "Mashtun" posted just recently that he purchased the Glutentox home screening gluten test, and started testing some beers. He tested Stone IPA, Corona, Kirin Ichiban, and even some home brewed Bock that contained a 20% wheat grain bill, and found them all to fall below 5ppm in gluten content. Seriously, this comment is the best source of beer gluten content I could find!
So none of this is peer reviewed science or official data. But going back to the "How fast can I speed and not get a ticket" analogy earlier in this thread, no police department is ever going to give you an official answer, either.
Personally, I've found darker beers to be problematic, but don't seem to get any reaction to Budweiser or Corona, or even Kona Lager, which appears to be brewed with wheat. Oddly, light beers (like Bud Light) have caused negative reactions, but regular Bud has not. Maybe light beers use some weird ingredients or process, I don't know. Going forward, I'll stick to the wheat-free lagers, not worry about the barley too much (it has much less gluten than wheat does), and grab a gluten free Greens when I want something more exotic. Greens is actually pretty good.