Chain halberd... sold! The hard part will be making them not look like a chain sword on a stick. I think I will have to resort to using SolidWorks and having these things 3D printed. Challenge... Accepted!!
As for developing more fluff, that will be put on the back burner. I have too many modeling projects that need finishing: more DWK, Shadow Ravens, Tac Marines, an Imperial Knight and a Silence Squadron. I think I will be making all of my assault marines as Shadow Ravens. The black armour works well for them as fast movers. Prehaps I will complete a few more squads of Black Lancers too.
Thanks for the ideas of tying the BoO psykers back to their homeworld. I never put much thought into it but there are some really great concepts like using the claws and fangs of the predatory beasts. The planet kind of has an Avatar feel to it except for the lack of really tall blue animal people.