You would need 326 TiVo Premier boxes to match what the Snapstream DVR can do with just one coax plug.
This Snapstream DVR is basically just a tech demo - but it's one hell of a tech demo. Loaded with 50 analogue tuners, it can pull and record 50 channels, simultaneously, from your cable feed onto 136TB of storage& - which is capable of saving 115,200 hours of recorded TV (or 13 years worth of content to watch).
Put differently, you could record 50 channels in your cable package for 96 days straight.
The system is driven by a 1U dual-processor, quad-core, Nehalem Xeon server with "a ton of RAM".
So what would this beast cost were Snapstream to actually sell it? Well a 4-10 tuner system with 3-15TB of storage goes for $US12,000. I'm guessing you can scale that cost appropriately, then add plenty of ??? to the price since it'd be a custom job. [Snapstream via Ubergizmo]