Sorry for the poor quality of the screenshots but here you go @Peltz
UI elements stay restricted to the original 16:9 aspect:
So text boxes are not resting on the bottom of the screen anymore:
The extra rendered parts of the top and bottom of the screen for 4:3 are not darkened for ui elements:
The unfortunate part is in a few places where the screen is normally fully blacked out you can still see the environment at the top and bottom.
But overall it is quite nice and seems to have no negative effects to frame rate:
I also uploaded the Gecko “GCT” code file I created that works for me: SX4P01.gct