University of Syracuse and Virginia Tech are leading the Wireless Grid Innovation Testbed (WGiT) with the goal of "coordinating knowledge sharing, defining key parameters for wireless grids network applications, dynamically connecting wired and wireless devices, content and users.
Another example is the Idaho National Laboratory established the Bechtel/INEEL Wireless Testbed. that offers end to end testing of next generation wireless including 3G/4G cellular and land mobile radios.
There's event a conference on the topic of building wireless test beds. You can see the current event here.