edit: whoa hang on.. i think this might be the one for you.. lens shift etcBENQ SP890 $2400
BUT 164" at 29ft Maybe a 180" screen would even work better for you?heres tons of reading on it
so how bare/flat/what color is the wall you would project? Reason i ask is once went to the trouble of setting up a large screen at a winery with a very difficult floorplan...and after it was over, realized the beige wall allowed for a much larger, higher image that still looked fine after a few adjustments. So for convenience and budget.. it is possible to not use a screen at all? otherwise, i'd see if you can stretch your budget. also, be aware that cables, mounts/shelves, installation could easily add a few 100 more to the cost. A spare bulb at 350 might be a good idea also with 50 people depending on it. Sometimes you can get deals/rebates for free bulbs.
anyway, hope this helps.
In cinema mode, seems the sp890 is closer to 2700 lumens.. but this light drop is typical of al lprojectors for accurate movie color.
Also, and this might be important.. The sp890 has a 2x color wheel. DLP projectors have a few advantages" purer whites, less "screen door" effect and perfect convergence but they have one major flaw: Rainbow effect. It's caused by colors being created in layers of red/green/blue many time per second. The problem is if you move your eyes rapidly, these layers of color separate. White stars on a black sky then look like a series of r/b/g dots. maybe only 10% of people are affected but it isn't just a visual distraction. For me personally, I get nauseous easily, and have headaches due to eyestrain that last a day or more. But that only happens to very few people.. still it might be something to consider since you intend a wide audience, and the benq is especially bright/slow color wheel.
here's an LCd projector that will work. it's much brighter than the ae7000panasonic pt-ar100U
is a very bright, LCD (no rainbows) super long throw (this kills the brightness) that will actually do 150" at 29ft. And it's cheap.. was 1000 last year, about 1300 nowhere's a thread from someone in a smilar situation as you, with good info on the panasonic
and some mentiontion of the sp890 also