As of January 1, 2009 it is no longer legal to import or sell 49-state emission legal catalytic converters in California; and that's why you will not find any online retailers shipping to CA. The fines are hefty and criminal charges can be filed for both purchaser and seller.
The allowed option is to replace your Toyota 4Runners catalytic converter with an inexpensive (compared to dealer item) OEM CAT which is California approved and has been given an Executive Order number.