I am with mac, although won't put it so delicately.
You don't want to do this project with projectors without complete buy-in from leadership.
Buy-in to the level that you basically have cart-blanche in what needs to be done to get this working correctly. That will entail pipe&drape (light control), modification of the stage lighting plots, possible modification of the finish of the stage, etc. This is regardless (and necessary) no matter how large the projectors.
Given those constraints I am lead to believe that doing this project as you current envision is just a Bad Idea. You guys need to either drop the project, get a major leadership thought change, or approach the project from a new direction.
In my (extension) church experience option 3, changing the approach, is usually the best option.
With that in mind: Build the whole project out of tiled low-profile-bezel LCD's.
Here are two import systems containing both the displays, processing, and available mounting options:
http://www.infocresttech.com/index.php?main=1&sub=0& catt=1&ssub=0&Language=us
http://www.primeview.biz/Otherwise you can also consider using displays with larger Bezels and integrated tiling software such as those available from NEC, Samsung, or Panasonic (Plasma)
Karl P