Bones post of rocket launches led me to this clip. This guy uses a piece of cyclone fence to make a launch surface for 8500 bottle rockets. There are several flavors of this same idea on the YT. This is one of the clearer looks into how to make it go. I like the idea and am looking into doing something similar. I think that you could be a little more creative with your fuzing so that it would start slow then take off to insanity. 
 Link This one (5000) shows the assembly and a different concept. 
 Link And the uber version (30,000) no sound at the start. 
 LINK  