Here's an idea, big epic thing that would take months to complete and run alongside normal contests - maybe as an annual thing for a photographer of the year award or similar, anyway here's the format
All as 'Free Study'
Firstly a qualifying round, run in a regular kinda way, the top 50% go through to round one (at this point it will be possible to know to the overall duration as numbers will be fixed).
Round One (and all rounds thereafter) the top 50% (or whatever percentile suits) go through, this is repeated until the final round (2 people at 50%, 5 people at 20% etc) and a winner is found.
i think that would be awesome. the only problem as i can see it is that it would take so long; any members who missed a challenge due to real life would be out of the whole thing for a year. I figure at a week per challenge it would have to be well over 2 months.
I figure it would take 10 to 12 weeks. Based on 400 entrants starting. 10 weeks would bring you down to three finalist for the ribbons.
That allows two weeks for the final three to do the last image for the big finale.
That is if you go with 50% elimination rate throughout.
400/ 200/ 100/ 50/ 25/ 12/ 6/ 3.
I've seen similar suggestions before and I like the idea even though I probably wouldn't make it passed the first round. I'd still like to see it as some sort of mass theme with each contest contributing to the theme.