Lords of Underearth
http://boardgamegeek.com/boardgame/5199/the-lords-of-underearth is a 1980s era microgame featuring tectical level combat between armies of dwarves, men and orcs in a vast underground dwarf kingdom. By blowing up a nicely redone version of the map,
http://boardgamegeek.com/image/243161/the-lords-of-underearth and replacing the counters with
40k minis, I have found it makes a marvelous system for gaming fights between orks and marines in an abandoned squat asteroid fortress (or you could use the squats themselves, if you have any).
Curious who uses other, non-
GW rules systems to represent battles of some aspect of the
40K universe that, perhaps, the published rules do not deal with?
40K submarines, anyone? What about man-to-man level starship boarding actions? Not in the Space Hulk sense, but actually fighting on the exterior of ships and drilling in?
Just curious.