Cheap POP-In-A-Box?

Interloper asks: "I have been considering creating a non-profit ISP for a small community. The idea is to provide dial-up v.34 or v.90 connections at cost. What hardware and software are available to make an all-in-one POP for dial-up users as cheaply as possible. The sort of features needed include WAN connectivity (upstream provider,frame-relay or leased line), a digital interface for a group of dial-up lines, internal routing, internal mail handling, authentication, and any other needed support for 8+ simultaneous users. Web page hosting is not considered necessary. Basically just e-mail and browsing. Can these features all be contained in one box? What distro and hardware would make this as cheap and fast as needed?"