I USE MY MAC ON MY 120" SCREEN & ITS AWESOME! I plop the iBook in & have a wireless (logitech) keyboard & gyro mouse. It works great, not choppy & resolution is fantastic. I get the sound in my (fakely-processed) 7.1 surround thru 28 speakers! I highly recommend the experience - even with my old G4.
Unfortunately I'm not smart enough to tell you exactly how the designer did it - he ran everything while the house was being built. Kinda the point of the forum, I know, sorry. Pic of the setup below - unfort screen is not online - its on Nemo video, but you get the point.
http://i242.photobucket.com/albums/ff176/Xinaspics/CIMG1064copy.jpg