Didn't see this until just today - a 6Gb mod for Thief 2 that adds a bunch of nice effects on actions, replaces some textures, generally improves and lushes out the environments, and covers the screen in goo.
Other parts, it simply renders the low poly architecture in HD, where some of the texture might seem a little under-scaled now are barely noticeable unless looking at that stuff.
Was at ttlg a while, but I read about it at steam discussions while posting about TDM v2.07 release.
It does make many of the T2 levels feel like a load of new maps, and I've been a little turned around in a few places as they are unrecognisable due to the update.
After searching here, there was no mention on the forums - so here's the trailer with some comparisons and a link to the massive download. I couldn't find a torrent.