This looks good! I know it need’s a little bit more work on the interface but it looks very promising.
I’ve been working on zenity to add a new –forms option based on bug #412493 requested by @aurium, and I believe it’s getting pretty good!
Right now I have –add-entry, –add-password and –add-calendar option. I need to work more in the calendar layout.
You can check the new option in the screenshot bellow:

zenity --forms option in action

If you have any ideas for this new option, feel free to post in comments