FreeGameDev

Zauberer is a libre, modified BSD-licensed content replacement for the GPL Hexen engine and is in early stages at the moment. The goal is to have a complete FPS/RPG game compatible with available Hexen mods. There is currently an Egyptian theme proposed. Those interested in checking out the current resource file in WAD format are welcome to Zauberer's GitHub at https://github.com/CireG/Zauberer
There is a discussion thread at Doomworld here: http://www.doomworld.com/vb/freedoom/72519-zauberer/
Feel free to ask anything about the project here!

Have you considered using free 3d models as placeholders?

Models by Gabriel Piacenti are well done and detailed enough for Doom's engine resolution:
http://opengameart.org/content/alien-charge-blaster
http://opengameart.org/content/skull-prop

Also, there is lot of free UI elements, although with non-BSD license.

For example I've recolored horned skull by Ravenmore (http://opengameart.org/content/fantasy- ... -ravenmore) into Hexen's palette:
https://github.com/saniv/free-game-art/ ... -skull.png

Cool project! Was actually thinking about playing Hexen a few days ago, and now this turns up! Doubt I can contribute, but I will bookmark this!

Thanks!