Emacs config. Latest versions of cabal cabal-install. A work around for the brokenness of the Haskell platform on ubuntu 13.04. Threadscope. Proper cabal setup for testing. Jenkins setup for CI from the start.
Also investigation dockerizing Haskell services too.
I'd be more than interested to see what you got. I want to introduce Haskell to our production soon, but am still not sure about the whole process of managing it at scale. This would definitely help as an info if nothing else.