Building Giant Robots is my answer to many things in life...innumerable anime and movies can't be wrong! Giant robots fix almost everything! Until they get smart enough to realize 'why do we listen to these meat-bags' but that's true for all robots.
That's why you use the power of friendship on the giant robots before they get smart, so when they are smart, you have a giant robot buddy.
I would use Mini Mecha. Like these. Once above Titnfall height they have to be really good to be useful