The typical asking rate per listing is in the $10's per square foot per year. The Shelburne submarket is experiencing a an increase in rates. In the last 3 months, the median rate rose $18 per sqft per year.
In the last 90 days, 3 listings have been listed, 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 available, so finding a space for a small business might be tough.
The standard measurement for office space in this area is around 900 sqft. Most buildings in this area are close to 3 floors. Most buildings in this market were built in 1870 and are Class B.