Call Dick Greenhaus at Camsco Music -- the phone number is toll-free (in the US) and is listed at the top of the page as "Record Shop." He might well be able to get the recoding for you, and if he can't he'll make a darned good try. (Buying from Dick also supports the DT and Mudcat.)

Another point, made earlier: if you have done all you can do and made a truly good faith effort, that's all you can do. Both the law and ethics doesn't require more.

Suppose you find a song by an Inuinnaqtun singer that totally blows you away. It's everything you like in a song. You do everything you have done before, but without results. Are you required to fly to Alert, Nunavet, Canada to do further searching? No (but you might want to go someday; the High Arctic is really a neat place).

You can only do the best you can.