Just before I made this post I was thinking the same thing, not using the whole mount but cutting the nose piece off and the rest in half and having two fan brackets!
Well here it is, a fan bracket made of T-7075 aluminum that takes a 40mm fan and fits a 42mm motor. Yes I made it and it's twin from a Tekno 42mm motor mount that I bought second hand for 20 bucks. That means 10 bucks per bracket plus fan that can be purchased for 8 to 10 bucks!
You knew there would be pics and here they are.