I've got three Tivos, so bit of a problem in a few months...
Each TV also has a raspberry PI attached, so am I right in thinking that the HD Homerun might be a good option? (rather than buy new boxes for each TV I can centralise a bit more).
Yes, IMHO, especially for those wanting a PVR in more than one location, the best system is to have a server and multiple frontends.
I have stated my preference earlier in this thread (MythTV) but there are others such as TVHeadend
You can also have multiple HDHomeruns to watch/record more channels simultaneously.