is there a way of running two (or N) galleries using the same code but different conf files (different DB/repository for photographs) ?
Looks like the requirements of using sockets instead of file handles for information access are a bit exaggerated. According to this Wiki SQLite support should be available in both Lenny-Backports and Sid.
However several Debian bugs may block some uses.
The Debian package seams to be lacking proper Dependants as well.
I'll work on removing these blockers, by the time this pages is updated Debian users should have a less complex Photo Gallery solution.