Hi,
I'm thrilled to hear that you are thinking of implementing an Impulse Modelling system to use with Garritan products.
I've had some great results using GPO with Voxengo's Pristine space e.g.:
http://www.last.fm/music/Dave+Elton/...+one?autostart

Is there any call for beta users or demo projects that combine GPO with IR? I'm sure I could redo that track as pure Garritan stuff if wanted.

Looking forward to it,
Dave