Heya, I'm on the exact same page around the 40k tie-ins. Honestly though, no mesh replacements or changes atm has us extremely limited. I've modded before for much older games, so I've started making a basic mod for fallout 4 combining parts of other mods and texture changes that's 40k themed. I'll link you to it once it's done.. but outside that I'm totally keen to help in my -somewhat limited- capacity for sure! :)