Linksys updated the firmware for their inexpensive WAP11 access point - $209 from Outpost.com - to allow this device to act as a bridge between wireless networks. However, even though the configuration is available, there's no documentation. I've contacted the company about this.
The advantage of a cheap wireless bridge means that you could operate multiple networks in adjacent facilities (or even thousands of feet away via line-of-sight antennas) and only have a high-speed Internet connection in one of them. Previously inexpensive access points would only bridge wired to wireless networks, allowing wireless laptops and computers to access the Internet via the access point. But a wireless bridge would allow an entire wired network to bridge to the Internet via a wireless hub.
Information from readers welcome as always.