Yeah, I'm working on an all new interface backend and a GUI tool that allows you to create/customize the interfaces. It's not going to be an open-ended as a fully scripted interface would be, but it will be highly customizable and offer just about every feature you can think of. I don't expect it to be perfect by any means, but I've examined the current code, and taken notes on the features that everyone has asked for over the past few years, and I think I've got something that will make everyone happy.
It will be tbl based, and can be changed and tweaked quite easily by modders. Each screen will be its own tbl file too, which should make things easier to keep up with. And it will have much better support for multi-resolution, which means that you can do a screen once and have it scale just the way that you want (ie, buttons could change position, but not size) for every resolution that a person might use. The editor will be sort of like creating a webpage in a WYSIWYG editor, coupled with an IDE. You create areas for playing animations, create boxes where text will go, etc. There will be things which must be on each screen (like the briefing must have a "Commit" type button to enter the mission), and a list of available locations to go (ie, techroom, missionsimulator, etc), but as much as possible will be optional and/or very customizable. You can use graphics and/or colored boxes to represent controls, so you could create a rather nice interface screen without using a single graphic file.
I also plan to create a very simple skeleton interface for modders to build on. This will give you every interface screen already created, using no graphics. Then a modder could easily edit the those screens to customize things to their liking, but they wouldn't have to create every screen in the game from scratch. That should greatly decrease the time and energy needed to create a customized interface, and also open that up to the smaller mods so that they could do some customization and include those change with a mod which would otherwise just be a mission pack.