Check this out. In my extremely limited experiences, this type of calculator is pretty conservative, and can be extended upon in the real world.
http://www.projectorcentral.com/Sanyo-PLV-1080HD-projection-calculator-pro.htm
doh, I see that tiger already linked it... anyways...
otherwise, my instinct right now tells me that I want to tell you to hold off to research more. A little part of me wants to see you get a better PJ too, but that's entirely easy for me to say. Just let me add that once you see how far money goes with a PJ, it will be easier to loosen the purse strings. PJs are
freaking amazing, and since IIRC this is in a basement . . . you'll most likely reap the benefits of any improvement.
I would first try to narrow it down between LCD and DLP I think, for instance. Hm, I guess I would probably go with LCD due to what will most likely be a lower noise floor and easier placement. However, if your placement flexibility is very good, then that won't matter. Hm.
BMX, where are you?