The typical asking rate per listing is in the $30's per square foot per year. The Danville region is going through a decline in rates. In the last 3 months, the median rate fell $3 per sqft per year. That's a 8% decrease in rent.
Compared to the rest of the East Bay market, the Danville region has lower rates, so you should have no trouble finding a great deal in this discounted region.
In the last 90 days, 9 listings have been posted online, which means new availabilities are probably leasing quickly. You'll want to be prepared to make an offer immediately. About 22% of the office spaces in the Danville are subleases, so you might be able to sign a shorter term by taking over a previous lease. 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 2,150 sqft. Most buildings in this region are around 2 stories. Most buildings in this area were built in 1982 and are Class B.