Trent Reznor does ambient? Not too sure, I know Aphex Twin does.
If you like rhythmic ambient, US Infraction label comes with some good releases, to name a few:
Tetsu Inoue - World Receiver (various versions with other labels)
Beautumn - White Coffee
MILIEU - Beyond the Sea Lies the Stars
For ambient techno or glitchy style, you may want to check NYC 12K, Japan Spekk and Germany Raster-Noton.
I personally like German AHORNFELDER, which releases quite atmospheric ambient...