There really is one basic limitation that a modulated system has...two, really...you can't distribute digital audio and you can'd distribute component video. If your customer wants to stay at that level of technology until the next time he decides to open up the walls (push push push sell sell sell), then modulated signals are fine. Note that modulated signals can be hard to use as the upper channels of cable now are pretty much filled with digital cable and the UHF channels are also pretty filled...so you can't have four or five channels like you used to be able to without killing some cable or UHF frequencies.

If you want to stick with higher quality, Audio Authority has a piece that can take one component, one composite, and two audio and distribute them to five locations...plus bridge out to more of the same unit if needed.

You could distribute component and use the NTSC in/out to distribute coaxial audio in order to deliver digital sound to the other rooms along with analog audio through the other two channels.