I don't know about you guys, but this is the first time I'm hearing about it, and I've had Men of War since it came out.
http://www.moddb.com/mods/stalker-mod
I was instantly blown away as soon as I saw their videos and how they even have anomalies! Looks totally awesome and they picked a good game to work with. Probably the only downside is that for their single player it will have to be a linear game, but they may have a way around that? Who knows. Anyway, definitely one to follow.