I don't remember where I got it anymore, but I found a C labs modulator that brings in composite (not component) video plus stereo audio and modulates it onto any channel you choose. I set it for channel 77 above the analog cable channels. That way I get the regular 70 or so analog channels plus my "TiVo channel" on all the other TVs in the house. The house already had an amplifier for driving all the TVs.
I installed a notch filter to remove channels 76-78 (Or something like that) from the incoming cable, and hooked up the modulator output and the notch filter output to a normal splitter (they work both ways unless specifically designed not to), and then drove the amplifier with that.
I don't have a good solution for controlling TiVo, other than the app on my phone.
If you have multiple TiVos or cable boxes you can get a multichannel modulator, which range in price considerably from reasonable all the way up to the dozens of channels used by hotels. I imagine the HD ones are getting reasonable now as well but I haven't looked.
- Sony S1 from 2001 with CacheCard+Ethernet
- Series 3 1TB, now with new power supply!