Still noi luck
Over a year later I still don't have a topcase fitted on my bike. Checking still daily the listings on e-Bay and Dutch (even German and French) listing sites but no luck.
Am a bit tired of it, maybe just stop looking and it will show up as a surprise?
In spring I'll make an appointment with a welder, hopefully he can make a custom rack.
I noticed the Renntec and Ventura options.
Renntect assured me that fitting a topcase is not safe; it could not handle the weight.
The Ventura rack is also not suited for a case; a bag is it's goal.
The Givi solution is really nice, that's nr. 1 on my short list.
More on this site then on my ZX-12R