Chuck, found this tangentially while attempting to find more about the
parametron, as per Dwight's message.
The Elliot 803 used core logic with solid-state amplifiers.
(Apparently core logic received more practical use than I thought, as well.)
Some description:
http://www.tech.port.ac.uk/staffweb/andersod/CCS/ShowPage.php?Page=19
Another description with diagram:
http://www.sli-institute.ac.uk/~bob/elliott803.htm
While it is AC-coupled, perhaps it is not what you were looking for, though.
The logic signal propagation still takes place in discrete, clocked, time
steps as opposed to continuous wave propagation, if that is an adequate
description of the distinction.