Buying SHAD in North America can be a challenge -- it *IS* possible.
A while back on the now defunct Honda CB250 Nighthawk Yahoo group, someone in a similar situation as @barbagris said that SHAD made a case for that bike.
The issue then was not so much the case -- cases can be had all day long from all kinds of places. The big selling point for SHAD for me, was they sold a mount.
It became an adventure.
I went to the SHAD dealer map (they show 77 dealers currently in the US -- including Hawaii) and started calling them starting the closest and expanding from there.
Eventually, I found a place with the right kind of parts guy, willing to be part of the adventure.
Me, "I'm looking for a SHAD case and adapter for . . . "
Parts, "What ? Who ? Never heard of them."
Me, "Their dealer map has your location and number on it, so I'm calling you."
Parts, "Really ? Hang on. [can hear him in the background - 'Have you heard of these people ? Where do we keep the old parts books?' -- he returns.]
"O.k. I guess we are on their list. We don't stock anything here. Let me make some phone calls, and I'll call you back."
A couple hours went by, and he did call. He said the distributor was "some guy in Miami" and he would place the order for me, and see what happened.
A few weeks later, I received the hardware at my house, and that case is excellent quality as is the mount, and serves on the back of the Nighthawk to this day.
I'm intrigued. I would like to obtain one.
And like others on here who have adapted cases to their bikes thanks to their creativity, ingenuity, and actual mechanical skills in which I'm woefully lacking, with enough energy and time, anything can be put on the Rocket.
If anyone is interested in a group buy (this would get more attention from both dealer and SHAD, I'm sure) I would be interested in doing it.
Perhaps @bedifferent or someone else would be willing to look at a mount (really, a vertical brace to reinforce the aft half of the box) ?