If I Were Creating An OSR DnD Product...

I would definitely be using someone like crazyred to draw my maps. Check out this wonderful underworld illustration. How about this outdoor map, evocative and DM-friendly, what with the imposed hexmap. And how about this interior illustration? It conveys infinitely more information about the environment, making it easy for the DM to describe what the players are seeing (or share the illustration with the players ... as they say, a picture is worth 1000 words).