rfernandez,
Take a look at Screen Goop. check out there web site. My friend did a 100" screen. They make 2 different colors depending on your projector. Whole process took 2 hrs to complete. The company actually states you should actually try to be a little sloppy and let the pait settle on its own to get the desired effect. The picture is amazing. $150 left him with $1500 he ended up putting towards his projector!