I have never heard of or seen a Hupfeld Unioliszt piano.  My thoughts
are that it may be a "badged" Phonoliszt -- that is, a standard Hupfeld
product that has been altered only in its outward appearance to become
a unique product of an up-market retailer.  The proof of its true model
type would be an internal inspection by a Hupfeld expert.  May I
suggest that Niels provides a few photos?

Nicholas Simons, GB