There is one wing design, the Saturday Night Special, that purposely has the flutes running in the spanwise direction for simplicity. It's a 4mm wing and the real beauty of that is the ailerons are part of the wing and not seperately added. The drawback is that it does create a faceted airfoil that is not as effecient at lower speeds, but does do ok. I've been thinking that it just may be possible on a wing such as this to treat a group (4-6 flutes maybe?) of flutes like a hinge at the apex of the airfoil, cut them out, and get a beautiful airfoil out of it. Just may have to do some experimenting

But when working with 2mm coroplast the chordwise flute airfoil comes out so sweet...it just can't be beat!