SonOfFree probably found something by now but for anyone else wondering, I have to recommend the Hifiman HF-801.
It works as a USB DAC and SDHC card player, and has an internal modular headphone amplifier.
It is the size of a 90's walkman but all-in-one with high quality Burr Brown 1704UK DAC and a line out to bypass the internal amp as needed.
Sound wise? Indeed! This is a great match to my Denon AH-D7000; full sounding, organic, very musical and non fatiguing... And because portability and simplicity (no extra bulk or additional cable cluster) are a must for me, it really answered all my needs (at about twice as less my original budget for separates!)
I suspect there is "better" sound signatures in separates out there but likely not for $790 (the Hifiman's cost) and certainly nothing that portable.
My two cents? Spend less, move more and enjoy musicality anywhere