HSWT is a project mainly written in HASKELL and JAVA, it's free.
Create SWT UI from Haskell
The HSWT project allows Haskell code to launch a SWT UI through the HJVM library.
The aim is to provide a native looking, cross platform UI solution to Haskell developers.
Also, to do something crazy involving Haskell, C, and Java. Fun, I tell you.