"The highly advanced id Tech 3 engine and free indie game project"
A 1280x1024 recording of XreaL
XreaL renderer to be ported to Wolf:ET
They abandoned Q3 for ET, but since project was not maintained for more than a year it is doubtful this will ever actually evolve into a finished game. Still, you can download pre-alpha which is based on Q3 and test it out.