I used a pair of ammo boxes on my NX650. I just bent some thick flat iron strips and screwed them to bike and boxes. Kept those strips as simple as possible, 1,5" wide, 1/4" thick, length as needed, 2 bends each, 2 pieces per box. Worked as a charm.
No pix on that, it was before the digicam was invented. But boy, did those heavy boxes way at the back make the NX a wheeliemachine
EDIT: Hej, it looked just like the KLR up there!