I'm dealing w/ a similar dilemma. Rapid Run is intriguing.

I went to a audio/video installation store and they gave me another idea. Monster has a coax cable made out of mini-coax but terminated w/ RCA. It's VERY thin, probably about 1/4 thickness of normal coax. Very flexible. I could see using this to run difficult routes since it's small, could be run under a carpet.

Your other option is to use video baluns from Muxlab. It converts signals over Cat5. The caveat (according to my dealer) is that you have to make sure that you use IEEE spec'ed Cat5E to make sure it's properly shielded. Then you can find very thin Cat5 cables for the long runs.