Hello Starke, like Cybershark mentioned, I have been working on a RTCW-styled wad aswell. My project is kinda dead, but if you wanna check out the first two maps of my project, download it here:
http://h1.ripway.com/Tuomio/pubrsldt_demo.zip
or here:
http://tuomio.oxyhost.com/pubrsldt_demo.zip
I hope you find some inspiration from my work, or maybe we can actually work together and share ideas.
EDIT: This wad works in ZDoom.