I think we're talking at cross-purposes about what we mean by 'No DRM'. The devices you're talking about would only run DRM free MP3s so in that respect they 'had no DRM', but they would be incapable of running DRM'd muic e.g. copied from a Zune or iPod.

But then Zunes and iPods could also always run DRM free MP3s copied from other sources as well, so I'm not sure what you think the difference was, or what advantage you think these independent players had with respect to DRM.