Tsk tsk - you need to think bigger. We're talking $550 here!
It sounds like the Sony Z1000 would be a good fit for you. I tried them out in Taipei and they have quite a bit of bass. Isolation is also good, and although they're on the small side, they are most definitely circumaural headphones.
You can also consider the Sony XB1000s and the audio-technica ES10s, although the ES10s are supraaural headphones and I haven't heard the XB1000s.