Thanks to the amazing work of mjn.mixael, we were able to build a fully functional, high resolution replacement for the initial pilot selection screen:

This screen is powered by libRocket framework which allows to create user interfaces in an HTML and CSS dialect. The logic of this screen is controlled by a Lua script so it is very easy to change the way the user interface behaves without having to change the FreeSpace Open source code.
The newly added barracks screen

The new in-game options menu:

The project has reached a state where the initial pilot selection and the barracks screens can be replaced completely with a libRocket powered UI.
The mod is available on
Knossos:
https://fsnebula.org/mod/UITestAlternatively, this is the development version which may be more recent if I bothered to upload the mod:
Here is the mod required for that:
http://www.mediafire.com/file/02evqpucyesvoni/libRocketMod.zipYou will need special builds to use this which can be found here:
http://swc.fs2downloads.com/builds/test/libRocket/The development version of this mod can be found in this open source repository:
https://github.com/asarium/libRocketModDevelopment of this project frequently happens via the #scp channel on Discord so if you want to follow the development of the other screens check out that channel.
Please test this and let us know what you think!
Again, huge thanks to mjn.mixael for making this project happen.