Hi, bonfoi, I can't commit to this because I already have too many projects going. I would be interested in reading the round-robin fic and possibly contributing to the next one.
Drabble length idea is pretty good, it could work. It's much easier to write a number of drabbles comparing to a one large piece. It's more fun too and people get to rotate entries faster.
My inner child likes the idea of having a prize on the end of it :)