The signal with the scart will be fine as far as distance, it'll be composite video, or component video, depending on what kit you have. don't think I've ever seen a long scart though, not that long anyway.
How are you intending to switch the slave monitor to see the required source?
Is this for watching Vids/DVDs only, or do you want broadcast on it too?
"I Agree with everything you say really!" - John Cooke to Jon Fuller - 26-01-2013