Here’s news from wi-fi infrastructure developers that are expanding spectrum available for such broad coverage of connectivity.
“Using Tropos’ recently-announced SABRE technology, operators can use policy-based routing to dynamically route traffic through unlicensed Wi-Fi, 4.9 GHz, licensed WiMAX or other links based on application, service, priority or other configurable rules.”
http://www.tropos.com/news/pressreleases/2007_03_27a.php