I've just got today the DAC E-MU 0204 USB and I can happily tell that it works on Linux (using the Arch Linux distro myself)
It was not automatic, though. I got the last alsa git repositories (kmirror and drivers) and had to recompile. If somebody is interested I will write a mini installation how-to.
Now listening to music using my new (and first!) DAC :D Rediscovering sound..... AMAZING