I can confirm that this $25 glass Toslink cable fits snugly into the Hugo and sounds great:
Perhaps topics on burn-in should go to another thread? A bit contested/ heated area...
Yup, mpd has been able to play dsd for a while now - almost two years if you're tracking git or vortexbox builds, as a matter of fact.
As for free dsd samples, maybe these; http://www.2l.no/hires/