Nice idea. I will try it if you write runGUI :-)
Sure, just let me know :) If this is to be done, I think it's better that the person writing the Haskell code do not write runGUI, so the implementation details wouln't discourage ideas that make life easier for users.
This is an imperative style library. For more Haskellian GUI library ideas, see Fruit (http://www.haskell.org/fruit/) and TVs (http://www.haskell.org/haskellwiki/TV). They may not pass the "builds" constraint :-P
I do remember looking at TVs and also Fudgets as sugested by Keith. But there's a unfilled hole for a library that's conceptually simple. I believe that with the library I described users (begginers in Haskell?) could even use QuickCheck and HUnit with their GUI code. Thanks for your comments, Maurício