I'm thinking if the projector were actually inside the cabinet he would have to do some serious heat venting. Those things get HOT and are not designed to be used in an enclosure. You can damage a projector like that just by unplugging it right after turning it off because the fan needs to run for another minute or two while the thing cools down.
Even if the projector were a cheapo LCD job it's working inside a small enclosed dark cabinet. A real projector like this Epson is going to have to be turned way down to minimum brightness or it's going to totally wash that material out.
Yep i agree with all of your points. All of these issues above are going to factor into the cab design, they're not easy to solve, but for me that's the biggest attraction and what makes the job worth attacking. I've been using projectors at home for about 10 years now so I've had a decent amount of exposure to their quirks and issues.
Here's my initial ideas to address those issues.
Heat - The PJ's will be mounted under the cabinet in their own housings for soundproofing with positive airflow forced through via extra fans, this setup is very common in home theater where you need to kill all fan noise by enclosing the PJ but then have to deal with the heat.
Turning on and off - I'll have to use an IR blaster that sends the double-tap shutdown command to the PJ's when a shutdown is initiated from windows, this will allow them to go through their proper cooling procedure.
Screen Washout - Highly unlikely with rear projection, plus I am using a dark gray/silver material to project onto. The uniform micro weave of Spandex essentially creates microscopic cells that capture the light hitting them, so it's not the same as blasting light at a reflective white/silver screen.