Yad (http://sourceforge.net/projects/yad-dialog/) is vastly superior to Zenity for the sort of things we wanted to do, at a fraction of the size (considering all dependencies). In TLXOS 3.x, we built yad debs using a DietPC build system (see yad_for_wheezy directory), because no Debian source was available for yad at the time, and we don't know how to construct proper deb sources. In our Jessie-based releases, we recompiled yad vs GTK2 to avoid a GTK3 dependency.