The Australian Tivo community is what inspired the AltEPG service. I don't know their current status but the AltEPG service software came from them (with some further adaptations of our own). They used the same hardware (Series 1 Tivo) but I don't know if they ran special software on the Tivo.
In the early days one or two of their team read our forums but I presume they do not any more. I suggest you start at
http://www.oztivo.net.
By the way, we don't say it enough, but the whole AltEPG community should be very grateful to the OzTivo people, who provided inspiration, software and help.