I live in So Cal, and bought a new truck in Texas this last August. It took two months to get it registered after I started the process with the DMV. Diesel or not, it MUST have the California sticker on it OR you must provide proof satisfactory to the DMV that a vehicle you were driving broke down and could not be repaired (at a "reasonable" cost). DMV decides what is reasonable, and you have to provide original (stress the ORIGINAL) repair estimates from a repair facility where you broke down.
The 7500 mile figure is correct; the law has changed some though. A few years ago you could go out of state, buy a new vehicle, drive it for 7500+ miles, bring it into CA and register it since it then had enough miles on it to be considered used. Now, you must show them the original sales contract which will specify the number of miles on the vehicle when you took delivery. If that number is under 7500, and you weren't in the "I broke down" situation, they will sell you a permit to get it back out of state!
I read through some of the information in the 2005 Mopar Service Manual, and there are some differences in the California trucks; none of the differences have to do with the heart of the engine, but there are additional electronics added to report specific problems to the driver or servicing dealer; nothing that effects engine performance or smog equipment.
I am like others in believing you can order a CA certified truck through a non-CA dealer. No one that I know has been able to get much of a deal on a CTD anywhere in CA!
Good luck. If you need more info, PM me. I'd like to know what you end up doing!