Anyone know why this was not manually-selectable on the Canon G9?

There's a special "ISO 3200" Scene Mode to use it, so it's odd to me one can't access it directly in Manual/Tv/Av modes.

Cheers,
ALF

because it's a "fake" ISO3200 which does pixel binning. the largest image size is something like 1600x1200 IIRC.