I agree that using Gtk is not ideal, but unfortunately I have no control over the modules installed on this system and Gtk is the only GUI toolkit installed. I will have to talk to the OS administrator for our systems to see if I can add it during the install of this script.
Thanks everyone for the help.
gnubbs
I have ended up using Gtk2. It requires my install script for this script to also install perl-glib and perl-gtk2 but that in the end is not as hard as getting this functionality in Gtk (not Gtk2). So, it will be Gtk2 and a list store.