Well I wanted something different, so here it is!
The 81st Catachan Regiment has been deployed on a Chaos-ridden planet for years. Such is their long campaign here, they have adapted to their more urbanised surroundings, and are a slightly different breed of Catachan as a result. Whilst never engaging a force directly, the Regiment has remained alive by harrassing and skirmishing, utilising guerilla warfare tactics to prove to be a significant thorn in the side of Chaos, without being a large enough threat to send a mass-force to hunt them down.
Usually the Catachans prey on the less-witted Cultists, dispatching of so many that they often make defensive barricades out of their corpses. They do occasionally hunt down a small amount of Chaos marines, using cat-and-mouse and hit-and-run tactics to run rings around their prey.
Here is the first squad, unpainted, unprimed - but assembled.
Caution - HUGE size pictures (Let's hope spoilers are fixed