this could work really well with a crafting table or a plinth specifically for making "quest" items.
so lets say we have an item that represents what is desired, an item that represents how many, and item that represents a reward (probably the reward itself would be the item, so like a bunch of coins, or a resource, this guarantees the quest-er gets paid). so for instance, in the plinth, id place in:
1 bone, to say i want bones,
a 5 rune to say i want 5 of them,
and 60 coins, to say id reward a player that much.
the item that comes out would be a flyer describing exactly that.
then the plinth could hold the quest flyer, and someone could come up and claim it.
then they would go out and gather, and drop the resources in the plinth, and the flyer would turn into the reward! easy peesy.
maybe this could be a purple clothed plinth? a quest plinth haha
and perhaps it could hold more than one quest flyer, that way you don't need a bunch all over your store, and people could browse the quests you want done, and pick and choose what they think is worth it/ what they want to do.
of course, if they receive coins from finishing your quest, and they turn it in at your quest plinth, which is already located in your store.....
EDIT: for larger amounts, you'd probably need to stack runes from 0-9, so like a rune of 6, then 0, then 1 would be asking for 601 of the item.
EDIT2: also, maybe the questing plinth would need charged with Spark, to make it a bit more balanced?
EDIT3: ive gone and gotten myself all hyped up for this now. this is an awesome idea @Dzchan94