Render labeller - Simple or not

I'm looking for a way to create some kind of UI where by you can load up the last render into a virtual frame buffer and then enter text into a text field overlayed on the top of it.

If possible I would write a which contained a text field for random notes regarding the render. Also checkboxes for FG/GI/Render-time tec. If these are checked then new virtual frame buffer window woul contain additional text fields which were populated with FG settings/Render-time etc.

This new virtual frame would have a save button much like the standard one but it would save the image with the new text overlayed on the image.

I basically want to know if this is possible at the moment as I dont have a lot of time to spend on it. If it is possible I'm happy to spend my time on it working it all out. Otherwise I dont want to waste valuable time chasing a pipe-dream.

Any info greatly appreciated.