I think I'm going to invest in a DVD that some pro haunters are offering on the topic of foamboard masonry. That plus papier mache, and the simple animatronics stuff (such as the kind used to make flying crank ghosts) make up the skills you need to produce a really great haunt.
I don't suppose anyone would like to go in with me on building a spectacular haunt one year for an epic party or something? I don't expect that sort of thing would turn out to be much of a money making venture, but if we put in a lot of our own labor (which, frankly, I would be utterly thrilled to do) we might break even.
Pipe dreams. Sigh.