[AZBBQGRILLS]

I can help you with your smoker needs. I build vertical smokers that have two to three racks 22 x 21 inches. I will be fabricating a smoker that will consist of 5 racks 7 inches between each rack. Thats enough room to cook 15 racks of ribs. The unit is built out of 10 gauge metal. Fire box will be 20 x 24. Mike here at AZ BBQ has one of my smaller smokers. What I can offer you is this. We can build your smoker for around a 1000.  As you grow in catering we can add a open face grill and as you get bigger add another smoker and put it on a trailer. Each addition will cost a little but it won't take a big bite out of your pocket to get started. I have a shop in Tucson. My website I www.azbbqgrills.com. 

[AzScott]

Maricopa County's website is a mess and doesn't seem to answer the questions you are looking for.  I think the best thing to do would be to go talk to their Environmental Health department in person and start running ideas by them.

[shishcabob]

I agree with Toys4dllr. Mike and Shelton at BBQ Island across from IKEA has one of the best selection in the Valley. I personally recommend The Good One PONY EXPRESS. This is the new 24" Open Range. Great for the starter BBQ-er. Good price easy to get into. The guys even rent one on a trailer.
Pellets I would go with the Louisiana Grill. It cooks hotter the the others (up to 600')so you can grill but also allows infinite control of pellet feed. I have never had food some moist yet so well done. Find out when the boys are demoing the grills and see for your self. They always seem to be cooking something.
Good Luck! Stop in and see me if you ever get to Havasu!