Very cool!
My husband and I are brand new to the tandem scene too and we've done two pretty good rides.
We found a nice bike for sale at a bike shop in UT, we are in Denver. We had them ship it. We got a $3K bike for $2K shipped. It's a brand new Co-Motion Primera from 2005. I'm in love with it already.

Check out craigslist for Santana, Cannondale, CoMotion and Trek.
Bet there are many in the SAn Fran area.