In which dialects does "is wanting" work as an appropriate substitution for "wants"?

Solution 1:

I can't conclusively say if this is a reflection of the dialect, but my mother-in-law uses this construction and she is from Arkansas.

Solution 2:

I think this is fairly common in speakers from north-east England and Scotland. As a child, we subscribed to the Beano comic, which was printed in Dundee, and characters would often use this sort of phrase, which sounded odd to my London-based family.