As to whether a class has a parallel heirachy or not depends on
how we define the use of the class.
It hardly matters, because there's no practical way to bootstrap a new
If all classes have the same root, the root servers for any new class
are the same as the ICANN managed root, and short of an implusible
revolt by the root server operators (one of which is of course ICANN),
they'll have the same management issues that the IN tree does.
Or if they don't have the same root, it's just another alt root, and
we know where that leads.
PS: I would also note that several special use TLDs do things you
can't even express in the DNS. When you resolve a .onion name,
you don't get an rrset, you get an open socket.