Wow this I did not expect. Warhammer 40,000: Dawn of War II and the expansions are showing signs that they will come over to Linux & SteamOS!
You can see the information from SteamDB here:
It also looks like Warhammer 40,000: Dawn of War II - Retribution will come to Linux too, again thanks to SteamDB.
While I am not a massive fan of Warhammer I've actually seen this game be played by an old friend of mine, and it genuinely looked quite fun. I am also a sucker for real time strategy games, so it appeals to me!
I wonder if it will be a outsourced port, or if it's in-house, but only time will tell.
Something to remember though: Being on SteamDB doesn't mean it's confirmed, but it certainly looks like someone is working on them.
About the game
Command any of the six unique factions in the next standalone expansion of the critically acclaimed Dawn of War real-time strategy franchise. Choose to build a massive army or lead a small squad of elite heroes into battle and experience a single player campaign customized to your favorite race. Go online and face off against your enemies and experience the fast brutal combat of the 41st millennium.