I don't have a link, but combined Solar Electric / Hot Water panels are relatively common Australia. My neighbor has them on his new house. I'll go ask him for details.
The problem will be getting regulatory approval. A high speed digital signal at VHF is going to radiate like blazes and wipe out FM Broadcast and hundreds of emergency services.
This system will face the same problems as BPL, only much, much worse.
The truth is that you can't reuse the (all ready full) radio spectrum, especially over copper.
The only way you can do it is with well shielded Coaxial Cable (eg Cable TV) or via light (eg Optical Fiber).
It's a triumph of Sales people over Engineering. Or to put it another way, the laws of physics will always win.