Sardinian?

Hi linguaphiles. At my job, a foreign bookstore, I have a client inquiring about materials in English or French for learning Sardinian up to an intermediate level. We have an unbelievably wide array of language learning materials and can supply many more but in my research I'm just not turning up anything besides the Talk Now! CD-ROM series, which I do not expect would be sufficient. Has anyone here studied Sardinian as an anglo- or francophone, and what have they used? (And yes, I've already checked Assimil, they do not have a Sardinian program... yet.)

Merci beaucoup, etc.!