Thats a good point, the more monstrous models might work with smaller scales.
Yeah, with supers as long as they aren't holding or standing on something that sharply defines a scale you can jam all sorts of "offsized" figs in - and that's before you consider size changers or stretchy guys. The Superfigs range from Old Glory is chock full of big 40mm plus sculpts and little 15-20mm shrinkies. Same goes for totally nonhuman stuff. How big an alien, or a robot, or even an ogre or giant?