Tropos announced its next generation of gear today, encompassing 802.11g speed: The new series of mesh Wi-Fi routers offers the higher speeds found in 802.11g, as well as support for a new mesh operating system and management console that offers more flexibility and support for security. (They're using Atheros chips, by the way.)
Tropos estimates that with $68,000 of their latest gear, one typical city square mile could offer 10 to 15 Mbps per user concurrently. They estimate a sevenfold higher cost for this throughput from other vendors; I'll be curious to see competitive math on that.
The Tropos 3210, an indoor mesh router, is shipping now, along with the 5210 outdoor router. The 4210 mobile router should be available by third quarter. The 4210 is designed for ad hoc access from non-fixed but static locations, according to an earlier press release.
The new management and operating system includes intra-router AES encryption support, which should answer one of the concerns I've heard raised about outdoor mesh Wi-Fi: with AES, there's virtually no opportunity to tap into communications between mesh nodes.
Now, there's definitely an issue of sniffing other users' traffic at any given node, however. The new system offers supports for up to 4095 VLANs and 16 ESSIDs, along with 802.1X and WPA support. This should make it much easier for metropolitan-scale networks to standardize on using 802.1X even for residential users connections to the network.
Take a Wi-Fi bridge with 802.1X client support as a CPE and set it up as the gateway using 802.1X with WPA Enterprise to a node using an ESSID reserved for that purpose and market it as secure access. Or support individual computer access using free built-in 802.1X software or Funk or Meetinghouse's $40-$50 clients for other platforms.
Other users can connect via insecure links but can be heavily warned about using SSL email and other security mechanisms. It can be a service differentiator.