Starting from aproxx. 3000 Lumen, DLP is quite okay to hit buildings.
Keep ambient light low - Street lights, Big Ads and stuff like that
kills every projection quite easily. Be aware of that while choosing
locations.
3K projectors are also quite small and easy to transport - also a big
plus.
We are using this NEC model (
http://www.aboutprojectors.com/NEC-NP61-
projector.html) to do small but pretty things.
mat