Hi Joel! I'm a nano. I run a 1 bbl brewhouse and have been in business for just about 2 years. There's a bunch of us around, but not an army. From what I've seen, I know of around a dozen nanos persistently operating out there and probably about twice that in planning/dream stages that might get off the ground. Or might not. Check out Hess Brewing's website. They're trying to keep a running list.
Healdsburg Beer Company
Sonoma County, California