As a "moderate-to-heavy" user of the BadGeometry Wiki (well, usage depends a lot on specific projects) I eagerly awaited the Return of The Wiki, now in its newest incarnation, ie., hosted by Linden Lab.
Since this did not seem to happen "immediatly", I wonder if something went wrong

If you want to consider a "permanent alternative", I have a Linux box somewhere in France, with pretty good connectivity, and would certainly be able to give anyone from the "Bad Geometry" group access to it to set up their own Wiki, no problem with that. Alternative: have some sort of "wiki web ring" with multiple copies (there are already a few around, I've noticed!) and a standard way to mirror them from a common source...