Building A Small Video-On-Demand System?

Ryan Mack asks: "My dorm is looking to build a small (4-8 user) Web-based video-on-demand system. Basically, we'd want to be able to schedule MPEG-1 or MPEG-2 streams to be decoded and sent over our building's unused cable TV distribution system. There are many PCI MPEG decoder cards, but few advertise Linux driver support, and none mention if multiple cards can be run in a single box. We've also looked at external MPEG decoding devices, but these require ATM, T1/E1, or high speed RS422 connections, which also raise Linux compatability concerns. Anybody done this before? Can anybody recommend a MPEG decoding card or a RS422 controller capable of 5 Mbps transfer?"