It looks like you would need to put a vent in the top if you don't have the BBQ Guru forced draft.
On a similar note I was just searching for a retail source of fireproof fabric. I have a crazy idea for a fireproof superinsulated bag that I could put hot stones and a dutch oven in and simulate cooking in a "beanhole" or pit bbq. I think I've decided to go with sheet metal and rockwool insulation instead of fabric.
