Audiophile portable CD an oxymoron?


I do a lot of listening on headphones. Although portability is not absolutely essential, is there really such a thing as an audiophile quality portable CD or do they all sound lousy compared to full size transports?
hnx
Optimus is a badge name for Radio Schack. Does Panasonic make the Optimus 3400?
Bmpnyc....no, this IS a Radio Shack product and was discontinued several years ago so you must find used. It is worth the hunt as the sound quality is significantly better than what's currently available. The 3400 also has a digital out and is often seen paired with the Audio Alchemy "dac in the box"(there has been one of these for sale here). This player had such a cult following that Dick Sequerra developed an elaborate power supply for the 3400 and several people used them as their main transport. I have been able to pick up two in mint shape over the last year and have been very happy with them as a potable solution.
OK, let me fill you in how what started this kick. I was about to steal the tubes out of my old HH Scott 222 stereo amp that I've had since new in the late 50's. Decided to try it has a headphone amp with an older Sony DISCMAN before decommissioning it and found it to be absolutely kick-ass! I may just move the Rega Planet over and buy something new for the main system. Still would be nice to have a quality portable.