Pizzagod,_one thing you seem to not understand is that CIS is just your agent. Progressive is your insurance company who writes the check for the repairs. They have nothing to do with the time needed to fix your Sprinter. The body shop that did the estimate is the one who told you the time frame.
Even if your van would be the only one there it would still take quite a while to fix all the damage. From my understanding you were hit in the rear pass quarter which spun you 180 degrees, and flipped you onto your drivers side. That's a substantial ammount of damage. At the very least all of the drivers side sheet metal and support structure would have to be cut out, new supports welded in and then new sheet metal installed. The damage to the passenger side where the hard hit took place could go as far as damage to the roof, floor, and frame/unibody, and rear doors. That's not to mention any damage to the suspension, rear end, drivetrain, air bag system, glass or light housings.
The shop has to basicly take apart and rebuild your whole van. That is a lot of parts to order and wait on to come in.
If you should be mad at anyone, it should be the person that hit you, also for the LEO not issuing a ticket to the person that hit you, which would put them at fault. I would try to go after their insurance company for down time to a work vehicle and loss wages while the vehicle is down. You never know, they night cover the cost of rental for a similar vehicle. As far as shopping around for insurance, go ahead, but you wount find a better policy for the price than thru CIS.