Yeah, see if you can do some recruiting on any other forums about Renegade or at least that have fans, like where you got some scans. This community, it's hard to find someone who isn't already working on 3+ things

Wow, I totally hadn't realized Renegade Legion was by FASA! Shoots it up in my esteem a couple notches... if it wasn't so hard to find I'd try the paper one out. I had the Battle for Jacob's Star aaaages ago, I should go dig it up.
I can't model, I'm a coder

But I do know it is hard but getting easier. PCS 2.0 is out, which is for converting finished models to the format Freespace uses. I think I heard work is being done on ways to convert from Blender, which I hear is easier / cheaper than some.
To the turret question... not sure, but you could probably make really big 'turrets' with 10+ firepoints?