Does anyone know if Google spreadsheets actually works if you have 50 people actively editing a large spreadsheet? I.e. Excel claims the same thing but has lots of problems with more than a few people actively editing a file.

My full question in the Doc's help form is at:
http://www.google.com/support/forum/p/Google+Docs/thread?tid=2d32aa15a78b4873&hl=en
and has not been answered.

Can't directly give an answer to you, but some time ago we – on blogoscoped – collaboratively made an artwork in google spreadsheets and at some moments more then 30 or 40 where in it editing without any problem, so I assume you it will work fine (can't find the file now, but here is an snapshot http://blogoscoped.com/files/collaborative-spreadsheet.html , gives you an idea of the amount of row in question)

Thanks, thats a good example, better than nothing.