On average, listings lease in the $20's per square foot per year. The Beachwood submarket is going through a decline in rates. In the last 3 months, the median rate fell $5 per sqft per year. That's a 18% decrease in rent.
In the last 90 days, 16 listings have been listed, which means spaces most likley are leasing quickly. You'll want to be prepared to make an offer immediately. About 6% of the office spaces in the Beachwood are subleases, so you will probably have to consider a longer term lease. 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 1,680 sqft. Most buildings in this market are close to 2 stories. Most buildings in this area were built in 1979 and are Class B.