Questions for Godspell 2012

My group is doing Godspell in October. This time I decided to go out for the show and made the main cast, so as a person who normally does the lights, video work, special effects and helps develop sets, I'm trying to get alot of things done early since I will have songs and a script to learn. So with that I have a question that is a little more on the tech and special effects side of things.For the beginning of show I want to create what looks like something crashing into the back of the stage, we have a huge screen that comes down behind the stage. Well, at impact, not only do I want the video to have the effect of smoke, which is not an issue, but I want a good size puff of smoke to come off the back of the stage and maybe a few pieces of paper to look like it damaged something, just for effect. As a group we have 2 smoke machines, but they don't throw smoke fast enough to create this effect and make it look right. We don't have a whole lot of room to work with, the stage is only 16' by 16' and don't want to spend a fortune on something. We also couldn't really use pirotechnics, too close to the audience and during Halloween, while doing a Haunted theatre, in this theatre, our smoke machines set the fire alarm off. I am open to any ideas, whether it just be ideas that you thought of or already proven ideas that you may have done once before.Thanks for all the help.