Way late now, but there are a number of 8" round lights available - look at off road/desert stuff then pick the "dual sport" version of the off road light (an off road light won't have a vertical divider and will blind oncoming traffic quite badly). There's even a small company that puts a 7" street-legal divided light in a 8" baja designs off road race light cage.
I really like the round light, just looks right to my eyes. The new light is way to small and looks unbalanced. I'm not a long time ducati person or a traditionalist so no emotional attachment involved.
If you want, a baja race light is designed to clamp to the upper legs of the fork tubes, I don't see why it wouldn't fit right onto the monster. I'm not sure whether the quick-change race cage would look awesome or awkward on the ducati - its sort of trellis-like and might work well.
Here's a 8" baja designs cage with a 7" trail tech street light on my XR
The top has a quick-adjuster for changing height too
