Maybe the DIY fog machine is the answer to your needs.
http://img.wonderhowto.com/img/12/7...fog-machine-for-your-halloween-party.w654.jpg
Also, video: http://www.youtube.com/watch?v=exKNbK7teQs
I would get an underbed storage bin, hot glue some ceramic tiles to the bottom and figure a way to mount a wire rack about 3 inches above that. Make a bunch of these DIY foggers. I wouldn't be surprised if you get a dozen or more into that bin. Light a bunch of tealight candles set out on the ceramic tiles, put the rack in place, then put the foggers on the rack. Let them get hot, then add fog juice to all the foggers. You'll probably be able to accomplish this for less than $30, and get better fog volume than you would using one of the high power fog machines.

http://img.wonderhowto.com/img/12/7...fog-machine-for-your-halloween-party.w654.jpg
Also, video: http://www.youtube.com/watch?v=exKNbK7teQs
I would get an underbed storage bin, hot glue some ceramic tiles to the bottom and figure a way to mount a wire rack about 3 inches above that. Make a bunch of these DIY foggers. I wouldn't be surprised if you get a dozen or more into that bin. Light a bunch of tealight candles set out on the ceramic tiles, put the rack in place, then put the foggers on the rack. Let them get hot, then add fog juice to all the foggers. You'll probably be able to accomplish this for less than $30, and get better fog volume than you would using one of the high power fog machines.