A race type scavenger hunt would be cool. I think something like this should be hosted / sponsored by CCP. It would have to be an event that’s conducted over a long period of time, about 3 to 4 weeks so that all players can have the chance to engage in it.
Items needed to be collected could be an assortment of stuff ranging from collectable fluff items to special rare items. Basically players would have to beg, buy, borrow, build and or steal the items needed to fill the list.
Reward payout could be split into 4 different levels ranging from Level 1 (small) to Level 4 (large). Reward payout would depend on amount of items collected:
Level 1 reward gained for having 25% of items collected.
Level 2 reward gained for having 50% of items collected.
Level 3 reward gained for having 75% of items collected.
Level 4 reward gained for having 100% of items collected.
In my opinion the actual reward gained per each level completed should include ISK and an assortment of various items that can be used in-game.