But... Why would you want this? The platform already includes a very good package manager (cabal). What I'd rather like to see is even better dependency handling (currently, version numbers are too important for what they say) and conflict handling.

The latter is partly solved by cabal-dev, which installs packages that are dependencies of a development tree in a sandbox. The former problem could be solved using type-based dependencies [1].

[1] http://skilpat.tumblr.com/post/9411500320/a-modular-package-...