Hi,

i am really happy about this lively discussion around Haskell (Mac) GUIs.

I might hint to two other options:

1) Eclipse's SWT wraps the native platform's toolkits quite sucessfully.

The platform-dependent bindings are mostly automatically generated, afaik.
Some time ago i summarized my thoughts about extending SWT's infrastructure/code for Haskell here:
http://www.reddit.com/r/haskell_proposals/comments/9w7nk/adjust_the_swt_binding_generators_for_haskell/

2) Ruby's Shoes provides simple native wrappers as i've pointed out on Reddit:
http://www.reddit.com/r/haskell/comments/he8pl/status_of_haskell_mac_guis_graphics/

Bye,

Lenny