I recently went all out and got hold of a few FW Death Guard upgrade kits, along with some Mk II and III heresy era legs and Maxmini biohazard backpacks. I'm pretty pleased with the results-- they all work together and give a cohesive look to the models. These have been primered white and given an airbrushed basecoat of old style Gretchin Green foundation paint.
This is my WIP Chaos Lord. He carries the Burning Brand of Skalathrax, modeled as a Nurgle toxin cannon with a fuel tank backpack (known at the gaming table as the Goop Gun). The base model is the chaos lord from Dark Vengeance. He obviously has a ways to go, but I like how he is shaping up. As usual, let me know what you think.