Let's see if this works........
Did not have much room in the garage to get a good angle so the proportion looks a little funny, but it snowed last night. Yes, snow. It looks a little larger in the side view picture than it looks in person, remember this is a 33l case, but the back view gives a better idea of the size. When it pops off, the mount looks pretty unobtrusive. If you go the Givi route, the Downtown mount I found cheapest at Tour and Ride, and the box was cheapest at Motorcycle Superstore I think (although it could have been Revzilla)
Either case would probably look good on your bike, but I think the Bestem I found on Amazon for about $90, and the Givi setup was $300 mount and box. I merely picked the Givi for a few reasons, was not sure the white would match on the Bestem, custom mounting bracket rather than universal, future interchangability with other Givi's if I want bigger, and a smaller case to begin with. But you probably can't go wrong for $90 and the Bestem.
Keep in mind on the Givi you would need to spend an additional $40 for the back rest pad, and if you want you can really pimp it out with the tail light kit and for $90 more dollars (hey why not spend almost $500 on a TOP CASE!) you can add the remote keyless entry for the case with a keyfob to pop the box lid from 50 feet. I might do that last one in the future just for giggles. Quality is excellent though, high quality double wall plastic with a pretty solid easy to latch and remove mounting system. It probably holds 3 to 4 decently stuffed plastic grocery bags, and I generally lightly smoosh a twelve pack under the seat with a little room to spare so it is big enough for errand running but the 42l Bestem is going to be about another 1/3 larger so you have to decide are you more concerned about capacity or it looking too huge.
Cortez has some pics somewhere of his Shad setup if you poke around a bit. I think his Shad is a 55l for touring if I remember correctly.