I did not find any official name for those backpacks, but they are characterized by a curved steel frame and a mesh, that allow good ventilation. Deuter sells them in their "Futura" line. The advantage of those packs is that they are ultra comfortable, as the mesh is adjustable and elastic. The cons are that you get less volume for the same size and long, rigid items do not fit well inside.
Are those backpacks convenient for backpacking? Maybe they have another pros and cons I have not mentioned?