Hi,
I have a partially functional NSBrowser in my PerlPad application.If anyone has (or is willing to develop :-) a trivial example of a multi-column NSBrowser, I'd love to see it. Until then, I'll hack on one and submit the usual partly-baked code snippets for help and comments.
You can get it at http://perl-pad.sourceforge.net/.
It is really incomplete, missing especially a proper display for the last column (where the Finder usually shows a big icon).
I hope it can help you to get started, though.
Also, there is a SimpleBrowser example in the documentation for the Developer Tools (in Objective-C, of course).
Good luck,
Thilo