I think I have finally made up my mind on what I think I want to do. I am making some sacrifices from my original 325 gallon plan after some great opinions from the experienced builders on this site.
As of now, I plan to cut off a portion of the rear of the tank to decrease the overall size from 325 gallon to approx 270 gallons. I am going to go with a 24"x32"x32" FB. According to the BBQ calcuator this should give me approx 120% FB capacity. If time, budget, and weight allow, I am going to explore the option of addidng a small (30" tall x 32" wide by 24" deep) warming cabinet above the FB. The cabinet will be heated by radiant/conductive heat from the FB only for now, but i might explore adding a opening from the FB later (hence the 120% FB size).
As DaveOmak pointed out before, the CC chamber size it not ideal for the best rack layout, but I think I will be able to live with it. According to my calcuations, I should have a total cooking grate area of almost 25 sq ft. which should be plenty for what I plan to do with it.
As I may have mentioned before, I work out of town and am only home 2 weekends each month. I have some steel ordered and plan to mount the tank to the trailer in a few weeks. I will post some pictures tonight of the cleaned up trailer.