On average, listings lease in the $20's per square foot per year. The Danville region is seeing a decrease in rates. In the last 3 months, the median rate fell $9 per sqft per year. That's a 24% decline in rent.
Compared to the rest of the East Bay market, the Danville submarket has lower rates, so you should have no trouble finding a great deal in this depreciated submarket.
In the last 90 days, 5 listings have come on the market, which means new listings are probably going fast. You'll want to be prepared to make an offer immediately. There aren't many listings below 2,000 square feet on the market, so finding a space for a small business might be tough.
The standard measurement for office space in this area is around 400 sqft. Most properties in this area are close to 2 floors. Most buildings in this market were built in 1982 and are Class B.