DEC made *many* hex modules that are not Unibus.
There are hex Omnibus
May not even be DEC, or for a DEC machine... Somewhere I have a thing
which claims to be a 370/E. I am not sure who made it, but I am told it
emulates the user-mode instruction set of an IBM370, but it's built from
F TTL on boards of the same form factor as DEC Hex boards.
-tony