Growth is not waning in the case of Panera. The 1,027-unit chain plans 170 to 180 new restaurants this year, up from 155 in 2006. About 60% of the St. Louis-based company's units are run by franchisees.

Panera might have a large unit count, but the company still has yet to rapidly expand in many West Coast markets, and until the pending purchase of a 44-unit chain called Paradise Café, didn't even have a presence in Phoenix. Plus, in many markets where there is a Panera presence, the chain has room for more density, stresses Neal Yanofsky, its president. "We're not seeing significant cannibalization," he says. "We're not feeling we're at saturation."

Kona Grill, based in Scottsdale, AZ, is on the other end of the spectrum. The company operates 14 restaurants across the country, but executives have big plans, seeing the potential for 100-plus units across the country in regional malls as well as lifestyle and power centers for the Asian- and American-themed chain.