How about a Bionicle RTS (real-time strategy) wargame.
Think about it, you could have all of the tribes act like factions. You can recruit Agori and Glatorians to fight against another tribe. You could even purchase upgrades for them. Then you can command them to fight each other.
I thought about modding my copy of Supreme Commander or Battle for Middle Earth 2 for bionicle, but I dont have the technical know-how to do it.