Bits of a Haskell Kit?

It seems to me that there is a need for the equivalent of the SML Kit, that is, a easily understandable and reusable compiler for the complete Haskell 98 language. The available Haskell compilers are not ideally suited for this purpose as they tend to be massive bodies of software of which it is hard to isolate components reusable in isolation. So far, the only two reusable pieces seems to be: