On average, listings lease in the $10's per square foot per year. The Roselle submarket is going through a an increase in rates. In the last 3 months, the median rate rose $1 per sqft per year. That's a 7% increase in rent.
Compared to the rest of the Chicagoland market, the Roselle submarket has less expensive rates, so you should have no trouble finding a great deal in this undervalued submarket.
In the last 90 days, 6 listings have come on the market, 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 posted, so finding a space for a small business might be tough.
The standard measurement for office space in this area is around 1,500 sqft. Most properties in this area are around 2 floors. Most buildings in this market were built in 2005 and are Class B.