I hadn't decided a setting yet, but I like the idea of a near future earth, or earth knock off. Possibly a frontier colony. Our characters could be settlers who build their own mechs and then explore, defend their home steads, combat each other. Maybe alien contact. Each pilot builds/ buys their own mechs which allows people to have various ones from various styles. If your character is part of a gang, maybe you'd pick a mechwarrior style. Boy genius might pick megas xlr. I'd say size cap on three or four stories, but we can go down to ten more realistically. They'd all be single piloted. That's my General idea