I don't think so. Afaik the GUI is made in Flash, and there's no supported way to change/replace/modify that code.
What if someone has Flash Professional (4, 5.5, 6, xxx) and/or FlashBuilder? Or if we use something like JPEXS [0] together with FlashDevelop? [1]
I'm curious because Skyrim's ui is also made with flash/scaleform and people could modify it (I believe by unpacking and fixing up things), and I would love to create a mini game as a mod which would probably require new menus (don't have editor access to check what's possible until monday when gog uploads it).
Is the scripting language powerful enough so we could use custom 3d objects to fake a menu?
[0]
https://www.free-decompiler.com/flash/features/[1]
http://flashdevelop.org/