I don't think you understand the cultural differences here versus there. My UDS is sometimes too big for my cooks, but, often, it is too small as well. In truth, the UDS is a marvel of efficiency.
In terms of firebox inside of a cooker, there are a few that are like that. But, the traditional side firebox, offset cooker is a proven design, that operates quite well for what it does. There are hundreds of variations, but, the side offset still holds the top spot for that kind of cooking.
"perhaps...but then again...maybe not..."
careful there son, those ribs are boiling hot...
(='.'=) Here there be bunnies...
Pacific Rim BBQ
Bob's Brew and Que