> > There's a plugin available for trac that might help with spam...

This needs version 0.10 of trac. I will have a lock at it. I might
just ditch the debian package and install trac from source.

> People who don't feel like fiddling with their install also sometimes
> publically post login information that anyone can use, because
Spammers will never look closely enough to find the information.

It seems that the spam is automated and targeted at "open" trac systems.
So, this would be an option but I am not sure how I feel about it.