How about "The Call of Cthulhu", by H.P. Lovercraft, or "The Masque of the Red Death" by Edgar Allen Poe. More recently we have "Hell House" by Matheson.
Yeah, there are many good possibilities, definitely. The mix of horror and comedy is what interests me.
I do have a particularly fondness for this story though, and the fact that it already exist as several musicals is not a factor. If that was a deal breaker, we wouldn't have the best versions of any of the classic tales , stories like Beauty and the beast (a musical long before Disney!), Treasure island (several versions)..or even the current uk version of this one.
These all time classic tales are sort of up for grabs, it's all about which version works for different contexts. High schools and local theater get to decide which version they want to do. I think if you did this one as a comedy first, but with dark humour and genuinely scary elements, it could be a much bigger hit for high schools for instance than the current most famous version.