Victor HA-NP1T2 ear-cuff earbuds fight sound leakage for about $130
Victor's second-generation nearphones cuff buds add a leakage reduction mode that cancels the sound escaping your ears, run nine hours a charge, and sell in Japan for about $130 with no US release planned.
We haven't written up this one. The Gadgeteer has the full story — the link below goes straight to it.