To the best of my knowledge no Hero contest has been concieved (yet). Why not update the original post to provide a starting point? Everyone else can then add their own recommendations.
~ Thread moved to Contest Submission.
In fact there has been a hero contest at WC3Campaigns, in that one, Daelin was the winner and I was in second place.
I know this is not important but... meh
A hero contest is the next level of a spell contest, it implies to make a melee hero (very important the word melee) with its 4 abilities (2 active abilities, one passive, or 3 actives, and ultimate). The most important requirement for this contest is the abilities must have synergy, which can be achieved by one passive ability that increase the effect of the other abilities, or the usage of one ability combined with other increase the effect on the target unit.
Why melee hero?? because the idea is to develop a
balanced one that can fit with the standard heroes in WC3, so a hero with abilities that destroy clusters of enemies with 10 mana and no cooldown are not allowed.
This kind of contest require to give a good price because it implies a lot of balance and functionality, to develop a good thematic for the hero, model, abilities icons, presentation etc. In general, it implies a lot of brain usage.
So if you want a pro contest, I suggest one of these.