I saw Ott play live in Richmond VA a few months ago. His set was fairly similar to that gnomelandia one, though I think he played longer. I talked to him for a bit after the show, quite a nice fellow, he showed me his setup - he was using two of those Korg tactile surface thingies for extra live beats and melodies, in addition to the obligatory laptop+mixer+ableton.
Before I ever played Quake, my favorite 3D game was Mechwarrior 2, which had an amazing ambient-tribal-orchestral soundtrack. It's been so many years, but I finally found it:
http://timur.iserver.net/mw2/
http://b19.org/music/JeehunHwang/
1st link has individual mp3's, 2nd has more complete zipped albums.
I also just discovered, while digging the above links up, that the game's composer, Jeehun Hwang, also did the music for the Hipnotic and Rogue Quake mission packs! So it is said in this interview:
http://www.soundonsound.com/sos/nov98/articles/jeehun.htm