when i lived in the east bay, there were no clubs per se that catered to this specific lifestyle. power exchange was always a mixed bag of wildly different interests & most of the other clubs were more couples clubs. on the other hand, there were groups(like "the crew")that threw semi-annual parties specifically for women looking for bbc & there were swing group gatherings(like "tangerine's dream" in san jose)the always had a great mix of folks. there were lots of "house parties" that catered to hot wives & it only took two of us ladies to rent a hotel room & invite our "friends" over & they always brought some friends too.
been in az now over 6 years, so i have no idea of the situation in the bay area now but i imagine things are still jumping.