On average, listings lease in the $30's per square foot per year. The East Bay region is going through a a rise in rates. In the last 3 months, the median rate increased $2 per sqft per year. That's a 7% rise in rent.
Compared to the rest of the East Bay market, the East Bay submarket has smaller rates, so you should have no trouble finding a great deal in this depreciated submarket.
In the last 90 days, 721 listings have been posted online, so you'll want to check back regularly for new listings. About 5% of the office spaces in the East Bay are subleases, so you will probably need to consider the implications of signing a direct lease with the building. There aren't many listings below 2,000 square feet posted, so finding a space for a small business might be tough.
The standard measurement for office space in this area is around 2,170 sqft. Most properties in this region are around 2 floors. Most buildings in this market were built in 1983 and are Class A.