What a great list! I'm a newcomer, and wanted to reply to a few
questions posed here.
 
As far as I know, there is no historical keyboard society in the SF Bay
Area, but as someone noted, the San Francisco Early Music Society is
very large and active. I've been a lifelong member and one-time newsletter
editor, and remember the first few years when the concerts were held in
a tiny church in San Francisco under a freeway ramp, and when a truck
went up the ramp you couldn't hear anything else. Now the concerts are
packed even in the largest churches in the area.
 
Laurette Goldberg founded MusicSources, a society/business out of her
house for promotion of early music, dance, and scholarship. She is supposed
to be retired, but is still quite active in various activities. She sells
keyboard instruments on consignment from her house, and often has very
interesting instruments for sale.
 
*****
 
Two years ago at the Berkeley Early Music Festival, in the area
assigned to instrument makers, I saw a really nifty tuning program that
runs on a Mac. It has some stored common temperaments, it lets you
modify them, or you can create your own. The volume went down quite
low, so it might work for clavichords. If you don't own a Mac, I
believe it will run on the most basic model, which wouldn't be
hard to find cheap. You would have to buy the sound card, of course.
Mark Anderson is the author, and I don't have an address for him but
could possibly track him down if anyone is interested.
 
*****
 
A word of introduction: like Justin, I have a single Flemish and I tune
by ear, mostly in Velotti. I learned to tune in a two-day workshop by
Davitt Maroney, and he somehow made it seem easy. I also use a tuning
of his.  Favorite composers are Froberger and L. Couperin.