>>11464673Try WWE stuff, might be a bit big but should work. There's also the Ramen Racer and other Ramen Toys stuff, though they can be a bit pricey.
As for mechs, the World of Halo Mantis actually has enough space in it's cockpit for 1:12 figures and G.I. Joe Classified is about to release it's SNAKE Armor, which is a massive bipedal mech suit.