I was also going to recommend Rockbox, but a quick look at the FAQ shows it is not supported yet. Neither does it seem to be supported by Amarok, gPodder, gtkpod, etc. which is a shame. I moved my primary workstation from Windows to Ubuntu last year and have been quite happy with a modified version of bashpodder and gtkpod. I prefer my podcast syncing/listening flow better now than I did with any of the Windows tools I used (Juice and iTunes).
I’ve been selfishly watching your progress on the ffado front as we have the same mixer and I haven’t taken the time to try it with Linux. Very sorry to see it isn’t yet working.
I was thinking along the lines of Jonathan above, however I think that the VM abstraction will bring too many additional variables to help much. You could, however, carve off a couple gigabytes from your Linux drive and simply install another instance on it. Make that your experimental partition and leave your “stable” Linux partition alone until you have a solution you are comfortable with.