[link|http://www.aminus.org/rbre/python|http://www.aminus.org/rbre/python]
The webapp framework is "Cation" and the ORM is "Dejavu". As I said, I haven't tested it on OSX, so it's a bit selfish of me to ask you to test it for me ;) You might want to try Todd's Seaside route first. Meh.
Here's a screenshot of my current directory page:
[link|http://www.aminus.org/dirsample.jpg|http://www.aminus.org/dirsample.jpg]