Jadeite
Hero
Their are usually two motivitations for creating a certain miniature (or any other piece of art): a desire to create it and getting paid for creating it. So, either find an artist that is willing to create what you want or start modelling yourself. Create a Kickstarter for stl files, printed minis or both. If you are afraid of being unable to fulfill too many orders, make it a limited run.
If you are succesful, you can propose your idea to a manufacturer like Reaper or WizKids, being able to present actual demand instead of hypothetical one.
If you are succesful, you can propose your idea to a manufacturer like Reaper or WizKids, being able to present actual demand instead of hypothetical one.