I think it would be pretty awesome to inject the WiFi RF into the coax of my home from the distribution panel. I only use the 1 line for my Comcast internet and ethernet/wifi to connect everything else. All of those other coax lines to each room are sitting entirely unused right now...

All you would need is a WiFi router that has a bunch of RG6 connectors on it. Wire in where the coax splitter/amplifier would normally live for CATV/satellite service. And then in each room where the coax feed ends up, simply screw on an antenna with matching RG6 connector.