Some upcoming Doom III modifications:
Remake of the original Doom using the D3 engine-http://www.ecs.soton.ac.uk/~aps303/doom3/cdoom/media.html
A Jedi mod-
http://www.planetdoom.com/doom3jedi/main.htm
Codename Reinforcements-
http://doom3.stormcraft.nl/phpBB/viewtopic.php?t=29
System Shock 2 - Reloaded
http://rebooted.purkaia.net/index.htm