There is already the nmedit project, which is trying to make an open
source editor for the nord modular. The format of the patch files are
quite well documented as well.
the windows emulator is actually running the software of the G2 on a
motorola emulator software.
I believe that actually with the G2 the format of the patch files have
become more closed source (not human readable anymore), so it would be
harder to do something there.
sincerely,
marije