what about a battle mansion type place. A place where all trainers go to meet and fight. The trainers can be different everyday. Each room is like a barrier, they can only be unlocked by getting the next badge(s). So with each room they get even more stronger.
example: we have 4 badges, so we get 1 room for each 2 badges. By obtaining the next bade(s) we get another room unlocked.
The trainers could be based off your design or they can be based off members on the forums, simply because on how funny some of the designs and interactions might be.