Yeah, it'd be hard to find open cans that are smaller like that. Maybe some on-ears like grado or something. The HD5XX series isn't too big, but they're not small like closed portables.Those AD900X look like they'd be quite big. I returned the SHP9500 for that reason. Even the Sennheiser 598 and 558 look big as well. The Sony MDR-10rbt I have seem to fit perfectly but even they are at the smallest size setting.