According to The Hollywood Reporter, Ahmet Zappa sold the idea to Benderspink and co-wrote an early draft of the script. Said script will go through some rewrites before going out to buyers.
Monster X stands for "Monster 10" as there are 10 monsters represented in all like Dracula, the Frankenstein monster, et al. This is all real early stuff, kiddies. We'll see if this one moves past the development stage and finds a home somewhere.