Yep, someone is doing exactly that with it as we speak :)
(Also, the only stupid question is one that you never ask)
Viewing post in Kesash's dynamic Renpy phone system comments
So every screen uses the phon_shell screen. So shrink the game area around the phone_shell, and then go into your screens.rpy and modify all the screens to use that phone_shell. It wouldnt be *easy*, if youre not good with screens specifically it could take alot of trial and error to make sure everything fits.
You would need to redo everything from the quit screen, to the save screen, to the help screen, etc.