One untapped modding area is the Steam players and Steam forums. There is less experince there and the forums are pretty sparse but new modders are bound to pop up there and it may be a great place to start something from scratch like this. Some people just want to be part of an effort and will join in. Might be worth a chance.
Any mod that succeeds will have to be a self effort. You may release a minimod easily--one that just changes a few things--but it will take a lot of time and patience to do a big mod--and especially any sort of total conversion.
The way to get other modder's help is to help other modders. Give models away, answer questions on entities when they are posted--or jump in the conversations and participate. Play and get on teamspeak and start developing friendships with other players.
I work myself and in the past four months, I offered to help a few modders in a very narrow way and as soon as I did got sent a list of things that if I had done them (and I don't have the time or even the knowledge to fully do them) I would have basically been creating their mod for them.
This is why most experienced modders seem close mouthed or non-committal when help is asked for. The other reason is about 90% of the "newest bestest ever" mod efforts get abandoned when the players who think them up realize it's going to be a LOT of work.
Most modders here are self taught and very few of them know how to mod every aspect of the game...meaning most modders would be hard pressed to do a real total conversion themselves. So when you aks them to help with everything, you're asking them to learn everything for you so they can do your mod. They are in the same boat already--trying to learn for themselves.
Your models are a great start. You really should start with texturing. If you can learn to use the Softimage Mod tool and make Sins textures for your models there, you will have something to offer other modders. Many need texture helkp and would gladly swap abilities and the like for it.
Get to know people, show in your topic what is unique and exciting about your mod and get to know people here. Gradually, as you get skills and show you aren't leaving people will bit by bit offer advice and the like.
Also, download, play through and look at other mods you like for ideas. Be sure to ask their creators for permission for anything you want to use yourself.
Here's the Modding section of the forums where you can start getting an idea of what you might be able to do or where to start:
A list of a lot of the essential tools and links you need to begin is here:
You can ask questions and get answers here:
Particle Forge Help is Here:
Sins Modding Wiki (Navigatable representation of entity syntax, constants, and constraints)
Harpo's Tools are here:
Harpo's Sins Utility Package -- Filefactory
Harpo's Sins Utility Package -- Dropbox
Rebellion Modding Topics are here:
Rebellion Modding Q & A
Changing Diplomacy Files to Rebellion
I hope this is a little helpful. If you have a team of friends already in RL, that is the best place to start--help each other as you learn.