Well, for anyone's future reference, I found an official document from the California Secretary Of State which discusses the issue
It looks like it's only a $70 fee to register... but then I have to pay the $800 a year like any california llc
http://www.ss.ca.gov/business/llc/forms/llc-5.pdf
Anyway, the reason I chose Delaware was because the identity of the members was confidential and not publicly disclosed - if I register as a foreign LLC in California is that no longer the case?
time to get an accountant, you're right.