I wouldn't call semolina unusual at all. De Cecco [1], probably the best of the bigger Italian brands, makes all their pasta products with 100% semolina (pasta di semola di grano duro). Bigger, cheaper brands such as Barilla use either the lower-grade durum flour or a mix of semolina and flour.
(For those confused with the terminology: Both come from durum wheat, but semolina is milled more coarsely from the bran, whereas durum flour is everything else, milled to a finer flour.