It appears that Games Workshop has filed suit against Chapterhouse Studios (makers of various resin conversion/upgrade kits for GW models) in the U.S. Northern District Court - Eastern Division (that's the U.S. court for all of us here in Chicago, for you non-lawyery types). Chapterhouse, based in Texas and Paulson Games, of Downer's Grove IL are named in the suit.
Amongst this otherwise typical copyright infringement case, GW's brief claims that Illinois (and specifically, Chicago) is it's largest market and goes on to name Adepticon as part of this claim! From the brief:
"22. The area in and around Chicago, Illinois is one of the most active for Games
Workshop, being part of the single largest selling market in the United States; being home to the AdeptiCon, the largest independent convention for miniature wargaming hobbyists in the country (at which the WARHAMMER and WARHAMMER 40,000 games are featured), and the site selected by Games Workshop for its 2011 Games Day Convention (which is expected to attract 3,000 or more fans of the WARHAMMER and WARHAMMER 40,000 games at the Donald E. Stephens Convention Center)."
IANAL but if you don't want to muddle through 18 pages of legalese, essentially GW is claiming that Chapterhouse is reproducing and selling the "unique characteristics and expressions" of GW copyrighted works and trademarks, most prominently their distribution of Space Marine shoulderpads with copyrighted iconography.
GW's first and second causes are general copyright infringement against GW and Warhammer, their third cause alleges deception and misleading origins of like products (which is why Chapterhouse now has a long disclaimer at the bottom of its site), their fourth through sixth causes allege copyright dilution, their seventh cause alleges deceptive business practices against GW's customer base, and their final cause alleges unfair competition.
GW is seeking a jury trial, destruction of all Chapterhouse's products and molds, triple damages, and court costs. All in all, I'd say the case is fairly cut-and-dry and Chapterhouse will lose.