Basically that. Create your own Battle Frontier. It can be mixes from what we already know, pure new concepts, pure old ones, etc. Give name to the facilities, a brief description of the mechanics, title and name of the Brain.

My ideas:

-Battle Mansion: 6 Pokemon each, 3 are randomly selected to battle. Lead by Mansion Noble Pinoh.
-Battle Puppet Theatre: 3 Pokemon each, 1 Pokemon can be swapped with the opponent (can be optional or arbitrary). Lead by Theatre Owner Shiela.
-Battle Ship: Weather and other field conditions can be seen in battle. Lead by Ship Admiral Francis.
-Battle Circus: Pokemon have no STAB. Lead by Circus Tamer Mike.
-Battle Circuit: After each turn, Pokemon are switched. If it was Rotation Battle, rotation is done strictly in one direction only. Lead by Circuit Ace Jeanne.

Your turn (hope this catches up)