I have made some modifications to the lhaskell.vim (v1.04) file to add a feature, and fix up some bugs. I don't know if this is the right place to post for patches, but the file I have claims that the haskell-cafe is the maintainer. First, I made it so that \begin{spec} and \end{spec} environments are recognised. This helps those of us who use lhs2TeX to document files. Second, I've fixed up the highlighting where inline Haskell between bars "|" used to be mistaken for verbatim text. There's also a small fix to handle \begin{code} \end{code} tags better. The modified file is attached.