I've just launched a new website hosting GS3 instruments. I've started with two, Percussion FX and a Peruvian Tarka Flute:
Articulations: Sustain Vibrato, Sustain Non Vibato, Staccato (4 way round robin), Portato (some velocity layered) and 25 short performances.
This website wil be updated every now and then.
EDIT: If the above link doesn't work, use this one: http://www.herman-witkam.com/raw/