If I can find someone with a different opinion, they can buy it and I'll use the money for something more fit for one of the purposes.
Meanwhile: " the solution must guarantee that no client can talk to any other local client (for fear of localized hacking),"
Localised hacking is a very fixable problem after all, you know where they live, but localised exchange is critical, unless you're a ticket-clipping obsessive.
ObURL: http://www.hpi.net/whitepapers/warta/ "This document exists to detail one solution to those looking to deploy authentication-based, for-profit, tiered network services over any Ethernet-based medium that utilizes industry standard protocols to tie in with existing OSS resources."