One more thing that might interest people: I just remembered the ISL59885 Sync Separator has an HD detect output. Pin 5 goes low when the sync signal is >25khz. Pretty useful for a X68k gaming and switching displays / outputs :)
Datasheet: http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=2&cad=rja&uact=8&ved=0CCoQFjAB&url=http%3A%2F%2Fwww.intersil.com%2Fdata%2Ffn%2Ffn7442.pdf&ei=VSvpU7zEHcXeoASwm4DIBQ&usg=AFQjCNFfyK0ljg8SW9Paxy4iOnIp20TPew&sig2=DFmJuJoGa1YLiyAre5lWXg&bvm=bv.72676100,d.cGU (http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=2&cad=rja&uact=8&ved=0CCoQFjAB&url=http%3A%2F%2Fwww.intersil.com%2Fdata%2Ffn%2Ffn7442.pdf&ei=VSvpU7zEHcXeoASwm4DIBQ&usg=AFQjCNFfyK0ljg8SW9Paxy4iOnIp20TPew&sig2=DFmJuJoGa1YLiyAre5lWXg&bvm=bv.72676100,d.cGU)
-Segasonicfan