That is a tough pair of shoes to fill. Can you define "a fortune"?
I wouldn't try to hit that screen with less than 10K lumens for a decent image indoors or out.
When you say patrons do you mean paying customers that will be irate if the quality is substandard??
First projector that come to mind is the Panasonic PT-DW10000. It's 10,000 lumens of 3chip DLP that's native 1920x1080. of course it will cost $45K-$50K
Otherwise check out the EIKI LC-XT4 for about $18K it's 12,000 lumens but is LCD and is only 1024 x 768 native. Not the greatest situation for a movie theater but will at least be bright enough.