I'm also interested in the same, but I'm willing to do it differently.
I'll first tell you all I thought about the mod, then you tell me how much you'd charge for it.
I can pay you half now, half when you're done. I'm also willing to pay monthly for the mod's development.
No matter which payment method you prefer, I'd like to also be updated on what features have been implemented and are working properly.
PM for further details, as I don't want to make all of my mod's features publicly available, as I fear a modder could "steal" my ideas.