Well, I considered making a diffuser out of some perforated metal, but I am going to hold off until I see how it cooks...
As for the 3 cooking levels, it's actually 2 with a 3rd rack to hold a water pan should I choose to put one it.
The fire box does rock! It can hold 1/2 bag of charcoal in it. This should allow for a really long burn. I have not discussed with him if he sells the fire boxes separate, but if you are interested, I can ask him. I am sure he would love to sell as much as he can even if it is pieced out.
As for the entire UDS, it is a little pricey, but the attention to detail and quality is outstanding. He cut no corners and has excellent workmanship... They go for $250 each. I was hesitant at first, but when I started weighing out the "time is money" factor (driving to pick up pieces, shipping, searching for parts, etc) I figured I got a great deal.
If anyone is interested in buying one of these, or the firebox, etc, please let me know.
I will post up some results here soon.