I guess any bid has to be realistic, and in line with the standards of
the day. We are currently between The Olympics and The Paralympics,
where there were 70,000 volunteers to drive down costs (called "Games
Makers") of running the London 2012 Games. And we assume that the London
2012 bid was funded.....
As for Wikimania bid costs (that is up to the bid being won) expenses
would be a good start.
And that other figure (of around £40K) perhaps could be a "no win, no