Get yourself 4 pairs of "broadband balun", let me know if it works. Search google. I found them as low as $60 each. 5 more conductors are needed as a minimum. This will not include the audio. I'm looking for the same thing. Or try the Video Ease I from muxlab. Looks like it has passive baluns for 3 pairs to 3 coax. This all doesnt look practical. I might be doing plaster work again cause I am thinking of running a new cable. or Extron Model DDTX DVI & DDRX DVI.