Going the CAT7 to HDMI route would give more flexibility.
Also talking to a TV engineer he say the only difference between the cheap HDMI cables and the more expensive ones is the build quality of the connector, he uses the cheap ones. The TV picture quality etc is the same and is more dependant on the make of TV.
I agree CAT5 to HDMI baluns are expensive I've seen them for about 65 pounds and you will need 2 plus this ones supplies the HD as three seprate components so you then have to add a component to HDMI adapter to that price. There maybe cheaper ones. try asking Keith on the Kat5 forum