I've recently had a couple of SD cards fail on me - to the point where Windows wouldn't even mount them or offer to let me reformat them.
Do you know if IsoBuster has the capability of accessing these devices at a lower level than a Windows mount to be able to try to recover data from them? By reading the IsoBuster website I suspect that that probably isn't possible; it seems like for flash media the system has to recognize it at least to the point where it'll let you try to format the media.
But if IsoBuster can do this I think I might be interested in trying it out (unfortunately, I've already thrown away the broken media so I can't readily test it).