We have only two HD receivers (one HD TiVo) and a standard definition D* TiVo, but nine televisions, two HD and seven standard.
First, I am a fan of the Terk powered multiswitches, but Winegard and some others make good ones. We have the Terk 5x8, which should work well for you as long as you do not have more than one TiVo (each TiVo needs two lines, do the math). Eight outputs should be enough for five boxes.
We have used the poor man solution of having only two HD locations, with our standard TiVo and D* tuner wired into a modulator which combines via a distribution hub with the antenna. This solution takes only three tuner boxes for nine TVs, but each can watch anything on the TiVo, anything on the antenna, and anything on satellite. The result is that we can go to any TV in the house, tune in channel 17, and watch whatever the output is on our standard def tuner/TiVo without having any additional boxes at each location (we have an RF remote expander, so you can carry one remote anywhere and watch the primary box on any one of the nine TVs, with the only additional wire being the one backwards from the modulator to the antenna wire hub-cheap, simple, but only for standard def). This solution would at least work for your non HD location, or if you decide not to have four HD boxes (very cool, by the way!). The location which feeds the modulator also has our older Sony HD-200 tuner, so the person there can watch some other program without upsetting the other TiVo out put. So, for instance, I can go to the gym TV, turn on a recorded TiVo or satellite show, and watch, even though the TV has no box, only an antenna wire. If my wife wanted to watch the source TV, she can use the other tuner in HD without disturbing my program. This does require one location with two lines for the TiVo, one for the antenna, one for the HD tuner and a line from the modulator back to the hub or multiswitch (five in all). But, I do not rent multiple boxes for nine TVs.
Satellite Guys is a reputable advisor and provider with the most solutions. They can help, but some aspects of your system you will want to be personally involved in. Good luck! Please come back and tell us what you ultimately do. Thanks.
