So after finally buying the game, like a year later :D
I attempted to continue this gui rework.
But the current GUI is such a mess in how it scales images non-uniformly making them look warped, it enlarges small textures and sometimes uses super huge textures that are resized to be extremely tiny in game.
It's a huge pain to work with because you can't get it to look good in-game.
So right now I'm pinning my hopes on 2.0, because I really hope 2.0 fixes the GUI for real.
I made this mockup last year and I'd really love to be able to make something like this.