Thanks for this tip. I do copious scripting on *nix machines, and I had not yet discovered these tools. I can see potential for creating much more user-friendly script widgets. I've discovered these tools on our Solaris systems as well. I found install instructions for MacOSX (http://zenity.darwinports.com) in case anyone is interested.

It looks to to me that portability has been considered -- at least for modern *nix systems.