Yes, I'd like to have one, too. How about this kind of deadline:
signing on: until Friday next week (giving everybody 13 days to do so);
Organising: Handing out the various assignments can be done over a weekend. I'd even be willing to do that. (That would be the Sunday after that - Feb 20th, right?)
Writing: 4 weeks? (Apr 20th?) 6 weeks? (May 3rd?)

How about it?

The only known quantity that moves faster than
light is the office grapevine. (from Nan's fabulous Home series)