that you tried it and it worked is more likely to get it uploaded sooner
In that case, I was able to add to my sources.list:
deb-src http://haskell-unsafe.alioth.debian.org/archive/amd64 . unstable
even though I'm using i386 testing/unstable (prefers testing), and use apt-src to build, ghc6, haskell-utils, haskell-mtl, haskell-stream, haskell-arrows.
The only issue is that you must remove all libghc6 packages and ghc6 packages before using dpkg to install new ones, to save a lot a headache with the package management system. Old libghc6-things don't seem to be removable once a new ghc6 is installed.
Also, I get this error on apt-src build haskell-opengl, which I have no idea about:
[34 of 84] Compiling Graphics.Rendering.OpenGL.GL.PixelRectangles.PixelMap ( Graphics/Rendering/OpenGL/GL/PixelRectangles/PixelMap.hs, dist/build/Graphics/Rendering/OpenGL/GL/PixelRectangles/PixelMap.o ) /tmp/ghc7639_0/ghc7639_0.split__65.s: Assembler messages:
/tmp/ghc7639_0/ghc7639_0.split__65.s:637:0: Error: unknown pseudo-op: `.ln.text' make: *** [build-stamp] Error 1 dpkg-buildpackage: failure: debian/rules build gave error exit status 2
Let me know what else I could do to help.