That's my issue--not the length, but the frequency. Once a week (more or less) for a month or two seems more likely to work for me, at least right now.
Of course, my schedule is definitely changing yet again at the end of the month, so who the heck knows at that point.
Why not make it a month-long event with different levels of 'commitment' for participants? If you have time, drive, and ideas for once a day, then do once a day. If once a week or twice a week is more your speed, that's also an option. If you'd like to participate but only wind up managing one story in the whole month, that's fine too. And in the meantime, we can all cheer each other on! A sort of 'choose your own pace' thing, a little bit like NaNo?
Your event, of course, and I have no idea what anyone else thinks, but that's my two cents.
~Z, well aware that pennies are out of circulation in at least Canada and, if memory serves, America as well