I agree, the earcups are not exactly large. They're a pretty cozy fit on me, but the earpads are very comfortable, even if they brush against my ears occasionally.
I can't remember if the earcups are any larger, but I briefly had the Phillips CitiScape Uptown headphones. They were definitely not as refined, with a big midbass bump, but were very comfortable and fun.
The Sennheiser HD 380 can probably accomodate larger ears better, and also isolates well and can fold flat for transport. It has a more neutral sound than the other two headphones I mentioned. It benefits a bit from a portable amp, but doesn't strictly need one. I never looked into it, but the stock coiled cable can be replaced with a straight cable. I had a pair that I used for travel for several years.
JakeMnz, if you have your heart set on the ATH-M50, I don't think you'll go wrong. Having never tried them myself (but I have tried a few lesser AT models), I can't compare how the fit or sound, but they have become sort of a classic, probably in part because they don't really do anything wrong.