Jeff, the original poster spoke of getting 'into the mobile business,' so that's why I'm thinking about commercial quantities.
It would probably require smaller sized parties, but, I think a WFO that can handle two 18" pizzas could support a New Haven style mobile pizza business.
Edit: I just did a quick search and it looks like most of the NH mobile businesses in CT are using WFOs. The Mugnaini's seem popular- which makes sense, since we know that they're not ideal for NP, but, as you work at lower temps, the heat tends to balance out. If I'm hearing the OP correctly, it sounds like he wants something like this, but on a trailer, not on a far more expensive truck.