I think they will ship to CA as long as they have a distributor outside CA for that product. The thing is, they refuse to charge sales tax outside MA state. At the same time, they also want to stay completely legit with sales tax code, so they won't ship an item to you from an in-state warehouse because they don't assess sales tax outside MA. I was told a long time ago they were going to fix this limitation, but apparently they are still helpless.
Most other etailers don't draw the line this sharp, and will ship to you tax-free as long as they don't physically have a retail presence in your state.
I did buy a Quantum 30 GB drive from them recently for $141 shipped to CA; it also is eligible for a $30 manufacturer's rebate (expired 9/30). This was a little more than the buy.com hot deal (at the time), but on the plus side I didn't have to play games w/ new account/email/CC just to get the discount.
Overall, I like NECX as a vendor because they have excellent product information. Unfortunately, they have slipped in the past year, while other etailers keep getting better (or folding).