OK, this afternoon I wrote a long response. I needed on bit of information to finish, but got distracted. When I came back, finished the post, and submitted it, I got a "token expired, go back and refresh the page". This, of course, means the whole response was lost. So:
I measured the shock off the Legend. Top mount is 1.180 wide. Bottom fork inside dimension is 1.210" wide. Fully extended was 13.25" center to center. Next I measured one of the mid '90's ZX9 shocks I have and it was 1.175" on the top and 1.290" on the bottom. It's not fully assembled so I couldn't get an accurate length, but I recall it's about 13.7".
Anyhow. I got a hold of a ZX9-ZX9R shock from 1994-'97. It has a separate reservoir like the TBS shock. The top bushing is the right ID for the Triumph bolt, as is the lower fork. They're easy to find, easy to install, and reasonably priced. The only problem is they're all pretty long in the tooth and need to be rebuilt. Find one with a good shaft as excess wear here will make it hard to seal. Rebuild parts are easy to find and member Rollinslow84 wrote up a good how-to procedure in this thread.
I am rebuilding mine with a RaceTech valve set up for a 170 lb rider on a Triumph TBS, and a spring from a TBS (supplied by Rollingslow84). If I ever finish, I'll post a ride report... TBS Spring is 12.3 kg/mm. The Kawa spring is 8.6 for '94-'96 and 10 for '97 so they're a little on the soft side. RaceTech recommends 11.6 for me.
Oh, just one more thing... There are a lot of shocks out there that take a smaller (10mm) top bolt. This can be corrected by replacing the top bushing with Kawasaki part number 92160-1161 (again, IIRC - this is for a 12mm bolt). The bottom fork is easy to drill out larger.