what a great idea, im sure it will be a huge success. friends of mine in denver usa have done this for years, it has grown to a point where they run 3-4 haunted houses annually. one year they bought rubber alien suit and props from a movie studio that was in the movie aliens and ran a haunted house they called "alien adventure". apparently you could only be in the suits for 5 mins at a time. they do really well and get over 50000 visitors each year for the month. they couple discounted entry for a canned food donation and donate tons and tons of canned food to homeless charities too..
have a look at www.scared.com for a list of their and other haunted houses running in denver this year.....