lanerd,
This is really something. We purchase our '04 Itasca Horizon, 36GD with the C-7 330 CAT back in May 25 of 2011. It was owned and operated in Nevada and Arizona but, had an LLC in Montana. We flew from San Diego to Reno NV to pick it up. It took us a couple of days to leaurely get it home.
Once we got it home, that's when I learned about the 14,000 lb. rule. Still, it took us about 1 day to get it registered. We did have to take it to the local CHP office for them to verify the VIN. Once that was done, we paid a local registration office (Private DMV registration business) a fee of $35.00 to register it for us. We had new title and plates in two days.
This was done in May of '11. If there's new rules about "CARB" compliant, over 14,000 lb. diesel registration, since that date, I'm not aware of them. Sorry for your issues. On a side note, we're tired of CA and all its issues, have been for years so, in not too short of time, we're moving to Havasu City in about 3 months when our new home will be completed.
I just talked with a DMV from Lake Havasu City and, to change our Drivers license to an AZ one, all that's done is, write them a check for, $20.00 for me, $20.00 for the wife, and an additional $7.00 for me to transfer my motorcycle license. A grand total of $47.00 for all that and NO TESTS ARE REQUIRED, YAHOOOOOOOO! As for vehicle registration, it will be the same, no issues.
Scott