I think that suggestion could work. My only reservation is that we had something quite similar before the Master Dare List (Weekly Dare Challenge) but it was a lot of work. I used to receive a lot of PMs and e-mails from people demanding to know why the threads had been locked (even though it said at the bottom of each thread), and when they weren’t locked, it was difficult to keep track of all the submissions (and to stop people posting stuff nicked from the web). The MDL was designed to solve the problems suffered by the weekly challenge.
Also, I’m not here consistently. Most days I’m around several times in the day, but I occasionally have weeks when I’ve got no time available. If we did it in some way where the weeks don’t have to be consecutive, that could work?