Yeah Ludum Dare is what made me think of a competition with Construct, since I don't want to wait 4 months between each comp, it would probably be a weekly or monthly thing.
I was also inspired by the 3DTotal competitions, they have weekly challenge and may have multiple challenges going on at the same, with different theme, going on for a while and allowing people for multiple entries.
For now I think it would be better to stick to the first idea which was a Ludum Dare like contest.
We will vote a theme and vote for the timezone the contest will be based on.
I will start looking around for prizes and judges.
@Ashely, would it be possible to get a new section for Challenges on the main forum page ?