Looks like something you could do with a drill and a saw 🙂
Have you tried Orange for a drawing or to see if they have one in a box somewhere (perhaps in a filing cabinet)
But for that, piece of bar, drill some holes (more holes = lighter 🙂 )then drill and cut the slot for the shock, not really seeing much need for any fancy machining. tricky bit would be getting the measurements for how far down the shock needs mounting but with enough holes in the frame mount you should be able to tune to your hearts content.
You could probably knock up a prototype in wood to check your angles out.