When I see them, the biggest I ever see is 27 inch frame (68.5 cm), which is almost always seat tube center to TOP, not center to center. I've stopped picking them up, donated the few I had left, never again. Extremely limited market, and based on your sizing request, a 27 inch one is too small. Sold the Fuji 27 incher that I had a few years back, it was center to top.

And many of the tall bikes had shortish top tubes. Bikes that would be square on smaller sizes didn't stay that way on the big ones.

I did have a Clark Kent custom once that was 74 cm center to top. Gave it away.

My guess is your Panasonic and Univega are both 27 inch center to top, at least all of the Panasonics and Univegas I have ever owned were sized in that matter.