xD. I'd actually do the quest for this
Bunny Top Hat [0] [Upper Head] Item ID# 5378 (Rabbit_Ear_Hat)
Type Armor Class Upper Headgear Weight 30
Defense 0
Description An energetic Bunny Band perfect for a magic show.
AGI + 3, Add chance of auto casting Level 5 Increase Agility when attacking.
However the problem I see is this. If it where to be compared to the ramen hat, one can assume a market entry price of 25 mil approx, so unless there is a way to balance this, like making it as part of an additional quest option for the event. Thus either a secondary reward for doing the quest or whatever.
Otherwise the hat would kinda be OP.
Linked to the zeny problem in heRO the hat can be a nice zink. Or even make it a farming intensive quest that can indirectly redistribute some zeny (for the long list of items needed, some coming from usual starting player training grounds) from the lazy to the not so lazy. So (hopefully more) new-ish players will benefit in comparison to more wealthy veterans.