I've been thinking about it for quite some time. I came second in a WFO tournament with this list:
Chaos 1500 list for WFO tournament:
Cithrik, Follower of Paths: Exalted Hero 201
Barded steed, shield, Mark of Nurgle, The Crimson Armor of Dargan, Biting Blade, Favor of the Gods
Nahrik, Seer of Paths: Sorcerer 210
Mark of Tzeentch, Disc of Tzeentch, Level 2, Book of Secrets, Dispel Scroll
The Harriers: 5 Marauder Horsemen 70
Light armor
The Harriers: 5 Marauder Horsemen 70
Light armor
The Trackers: 5 Hounds 30
The Trackers: 5 Hounds 30
The Rotters: 5 Chaos Knights 315
Lances, Mark of Tzeentch, Standard, Musician, The Blasted Standard
The Bonecrunchers: 3 Dragon Ogres 195
The Bonecrunchers: 3 Dragon Ogres 195
The Blessed: 2 Chaos Spawn 170
Mark of Nurgle
Points: 1496
PD: 5
DD: 3 + 1 scroll
Models: 35
Which was a blast (and challenge) to play, and offers some nice modelling opportunities.
I think I'm talking myself into it writing this post.
And no, I'm not too worried about the great sin of mixing Nurgle with Tzeentch. I'm sure I can justify it somehow.
EDIT: Oh, GP, on the painting side, this army is simply fantastic:
http://asrai.org/viewtopic.php?f=2&t=13392 (yes I know it's from the Wood Elf site, but it's a WoC army)