I agree that people could lose interest/forget about the competition more easily with this great a period of time, but even the 2 and a halfish months we alotted last time managed to leave some people upset that time was short, they didn't know about it soon enough.
...or perhaps those were just procrastinators pinning the blame on something else *cough-friendlyHunter-cough*
I can only assume that the best way to encourage maximum output of entries is to:
a) Keep the thread alive and interesting. (Teaser screen caps? Viewing party plans? Concepts? Art? Example videos of something you want to achieve? Collabs?)
Remind the world that even small, quick, silly submissions still provide a welcome change of pace... and even an hour of fiddling around with setting footage to an OCRemix or shooting video of your room is welcome.
A QUICK NOTE TO THOSE LOOKING FOR IDEAS
I highly recommend putting yourself in a situation where you're able to listen to mass amounts of ocremixes on your ipod or other portable music device... whether it's on the way to work, at the gym, walking to/from school, where ever; and just think about what would go with the music.
I've been doing this nearly daily for a while now and I easily have 8 or 9 solid video concepts. Seriously. I'm not intending to put anyone down for a lack of creativity but I'm in a situation where my biggest problem is choosing which ONE I want to do.