First of all, welcome to the TDR.
Being new you may not be too familiar with the search feature for the forums, but give it a try. Try "air bags" and you will get a ton of info.
IMO, since you will be constantly carrying the weight of the service bed (unlike the guys with slide in campers and 5'ers) you would be better off with a rebuilt spring pack. You will get increased capacity that is tailored to your load and you will likely get as good of a ride as stock, or better.
Bags that are designed to increase the capacity of the springs may not be your best bet. I don't think this is a wise choice for a permanent weight carrying situation. You can try a true air ride setup, but they are rather spendy.
You you might consider the RAS (Roadmaster Active Suspension, try a search again) as another alternative, but I don't think this is truely a permanet fix to your situation.
My $. 02
Ryan