I made the 'king of the hill' scenario, but computer troubles have kept me from testing and debugging it. Once released, it'll be the most commented scenario of all time, great for newbies to learn from too! Of course, I used sucky programming techniques for it, and a lot of things can be improved once timers are released.
I like that battle machine idea. If I make the battle machine an ally unit (similar to how storming does), then it's impossible to cheat. However, I'd prefer it if there was timers, so that the battle machine would give you three minutes to prepare, then attack, two minute pause, attack next base, so on...