I owned a Univega Specialissima back in the day. It was my understanding at the time -- based on close study of the bikes when I was shopping -- and I have read here at BF that the Univega Specialissima is the same frame as the Miyata 1000.
I also believe that the Univega Gran Turismo is the same frame as a lesser Miyata (the 610?).
This has been discussed on prior BF Univega/Miyata threads...
For anyone shopping, the Univegas are typically available for less money than the Miyata.