For those interested:
Last week, someone registered an account on some french gaming forums and released new, unofficial patches for Thief, Thief 2, and System Shock 2. It allows those games to run on modern hardware and operating systems, and brings all sorts of new bells and whistles to the game editor.
I'd describe what the patch is capable of, but I'll let this screen shot by TTLG forum user SlipTip do the talking:
Yes, this is a 10+ year old game engine,those are dynamic shadows, and each surface has it's own 2400 x 2400 texture! Granted, an entire level like this would melt most people's graphic cards, but just being able to -make- it is an achievement! (EDIT TO CLARIFY: The default game does NOT look like that. This is a custom-built room and textures. This is showing that the Dark engine is now capable of, not what you'll see if you get the patch. The patch does not come with any new textures or meshes)
Links here: http://www.ttlg.com/forums/showthread.php?t=140085
That post also has the original demos of both games ported over to the updated engine if you wanna give thieving or shocking systems a try.