I would actually sell the C-5xeMP and look for a used DX-5 DSD. It can play music off hard drives and serve as a USB DAC for a computer in addition to handling your physical media - CD, SACD, DVD, Blu-ray, etc.
EDIT - I should add that it seems for the thumb drive / hard drive functionality to work, it needs to be formatted using the FAT or FAT32 file system, a possible monkey wrench to this scenario.
EDIT - I should add that it seems for the thumb drive / hard drive functionality to work, it needs to be formatted using the FAT or FAT32 file system, a possible monkey wrench to this scenario.