Where can I find rent data for retail tenants?

[Daniel Alfandre]

Other than Costar and talking with brokers, does anyone know of other databases/sources that have retail rent data?  I want to run some scenarios of increased revenue if I were to renovate a strip center and increase rents.  For instance, how much do the Dunkins in the area pay?  How much do certain mom and pops (nails, barbers, etc.) in similar properties pay?