Hello, @zania! I'm not 100% sure, but I know that there is no chance of doing it without King's permission because it is their rewards that would be given out. If you have an idea for a contest, I'm sure King would consider using it. I'll tag @QueenB to see if she has anything to add. Have a great day!
Only the CM can post competition with Gold bars as rewards. If you have an idea, send me a private message with your ideas and lets talk and see what we can do 😉