Bat Boy IIIIIS a great, fun, show. I music directed the show about a year ago in a very small theatre with minimal set, costumes, etc, and audiences seemed to love it. Royalties aren't that expensive compared to other shows. The music can be challenging for amateurs, but pays off in a big way! As others have said, check out these websites for more info on other small cast musicals... (some of my favorites are Lucky Stiff, Little Shop of Horrors, I Love You You're Perfect Now Change, Floyd Collins. Each show has it's challenges/problems/audience draw, but they're some of MY favorites)
www.samuelfrench.com (Samuel French of course)
www.dramatists.com (Dramatists Play Service)
www.mtishows.com (Music Theatre International)
www.tams-witmark.com (duh)
www.rnh.com (Rodgers & Hammerstein Theatre Library)
www.broadwayplaypubl.com (Broadway Play Publishing Co)
From the evil she done Lord
Set her free, Set her free, Set me free
Don't let my sorrow
Make evil of me