In my opinion and my experience, I wouldn't use Ethernet over power adaptors. I've had no end of problems with them, especially where uninterrupted data streams are needed.
With the growing amount of online streaming content being pushed at us by the TV channels themselves and the growing use of voice over IP for reduced call costs, teleworking etc, powerline adaptors, even the 200mb/s ones suffer dropouts too frequently.
I'd definitely go back to the planning stage and install at least 2 runs of Cat5e/Cat6 to each room you want data in. You can use adaptors to convert RJ45 down to BT431A socket and then use a patching system in your wiring closet to allocate services to ports.
I completely Cat6 cabled my place but I use voice over IP exclusively so I just have 100mbps switches in the rooms where more than 2 ports are needed.
As for 1 service, 1 cable, I agree, however, there are a growing number of faceplates on the market that accept one 4-pair cable, however, these seem to go through some electronics which maybe reduces the near-end cross-talk issues to at least allow 10mbps.
I wouldn't use these at all.
My specification would be a central patch panel for your data sockets and distribute regular telephony through the same system on ports needed.
I've mostly done this in homes with small PBX systems to allow multiple lines but i'm sure you could build a bus-bar style patch panel with one in for the main phoneline passing the signal along to patch points as needed.
Don't forget about primary and secondary socket considerations when doing telephony, there are RJ45 to BT431A adaptors available for master and slave configurations. If you're building a patch network I would come from the primary master and 3-wire into your bus-bar panel and use the appropriate secondary convertor to plug into in the rooms.