Dazzling,
Wow, you're really eliminating a lot of contenders, although truth be told, I find the ear-canal ear buds (and I have some very good and expensive ones) oddly uncomfortable for long-term listening. I just don't like the sensation of those things inside my ears after about a half-hour. But I'm in the minority on that score.
I haven't heard B&O headphones in years; perhaps they are making some good ones. In the vinyl era, B&O made phono cartridges that were quite good (though not nearly as good as Grado, Shure or AKG, to mention other transducer specialists) so they know transducer technology. But among headphone connoisseurs, I haven't heard anyone recommend B&O headphones (or speakers, for that matter) in many years. However, if you've accommodated the tonal balance of the B&O's as your reference, then others may simply not measure up. Or perhaps the B&Os really ARE that good.
Check out the head-fi web site for portable little headphone preamps that allow you to use home phones you like with portable gear. Then you could choose from a variety of very good models.
Regards,
