If I could just interject a few things.
1. I have heard at least one Texas pitmaster, John Fullilove describe his cooking operation, and he is not cooking his meats for 12 to 16 hours, nor do they cook through the night. He run's the pits for Smitty's and he says they fire the pits at 4 or 5 in the morning and are serving by 11 a.m. By my calculations, that is a 6 hour brisket.
2. Countryboy, have you ever cooked in a restaurant situation? I recognize that you have a standard that you want to hit. But, cooking for a restaurant is a lot different than cooking for catering or backyard. If you have, then all kudos to you going forward with a plan. But, my experience has been that you have a lot of compromises along the way, to getting where you want to go.
3. I have had good BBQ off of a Southern Pride and a Frederich, it isn't all about the cooker. You can cook great BBQ off of a gas or electric smoker, if you want it badly enough. But, wood is expensive, storing it is expensive, firing it is expensive. A lot of those folks who are serving bad BBQ, are doing so, in order to stay in business. Believe it or not, most folks, anywhere, can't or don't care. Now, that doesn't mean you shouldn't, but, it does mean you will be putting a lot of effort where it has only moderate bang.