On average, listings lease in the $20's per square foot per year. The Southlake submarket is going through a a rise in rates. In the last 3 months, the median rate rose $5 per sqft per year. That's a 22% rise in rent.
Compared to the rest of the DFW Metroplex market, the Southlake submarket has more expensive rates, and you'll have to negotiate above asking rent to be in this hot submarket.
In the last 90 days, 27 listings have been posted online, which means leases are probably leasing quickly. 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 2,090 sqft. Most buildings in this region are close to 1 floors. Most buildings in this market were built in 2005 and are Class A.