With WordPress Version 3.0 I planned to rework the support for WPMU, as the maintaining is a bit easier for me. I created a issue at my GoogleCode project where you can add feature request for a WPMU/Multisite environment:
http://code.google.com/p/nextgen-gallery/issues/detail?id=286
As I didn't know the requirements for WPMU Site admins, I'm happy about any code contribution and tips for a better WPMU support
