Letter of Recommendation Coordination? I am currently applying for a research/study grant, and need three letters of reference. Would it be out of line to ask the recommenders to coordinate with one another so that they don't say anything conflicting, and don't double up on the same exact content? Not sure what the norms are.
It's certainly a good thought to make sure your letter writers don't double up on information to the detriment of their unique perspectives. 

However, it certainly sends an odd vibe to ask that they three communicate with each other to do this ... They are doing you a favor writing the letter in the first place, but adding to that to try and make them coordinate with two other professors is a huge load, and plus, if you want three professors to work together, you might get your letters in a year, if they aren't too busy.

That said, it's absolutely normal to talk to one professor and ask her to write about your programming abilities in particular, and to ask a second to talk about how you are a quick study, etc., so that the letters are complementary.