Lots of aerofoils used at the dawn of flight were 'concave' - the Wright flyer, Bleriot, Nieuport and, to a lesser degree, later ones too, such as the Fokker Dr 1 (Triplane) and Sopwith Camel.
However, even if you just had a single 'sheet' curved aerofoil, it would still have a top and a bottom.
Magnetic monopoles made from an Unobtanium/Eludium wishalloy might fit the bill
The whole concept of 'which part of the wing makes the lift' is bunkum. You could make a 'lifting surface' out of a rotating cylinder...
;^)
B.