there is already a permanent shelf for stories that win contests, it’s on the Contest Winner’s shelf.
How exactly would it be decided who is “small” and “middle”? How would such a contest even work?
Let’s say a contest just for authors with less than 10k reads in total. You have 7k reads and you’re writing to enter the next contest, suddenly one week before deadline your already published story gets on a regular Friday shelf and you get 5k reads more, now you’re at 11k total, you can’t enter anymore cause you’re no longer eligible for this “small” author contest.
No author has control over their reads or followers. There’s no ideal way to determine who is “big”, “middle” or “small” author. Maybe like community created contests could have reads limit or something but not an official Episode one.