A quick google search found:
https://groups.google.com/d/msg/comp.os.linux.m68k/-8iweTkxPNI/L2-hPrW_ryAJ
mentions:
I have an ancient Unix system made by ProComp in Switzerland that has a
68000 CPU, 4 MB RAM and that 68451 MMU. Unfortunately, I didn't get a hard disk
or system media for this oldtimer :( It ran a port of 7th edition Unix as well
as some System III variant. Would surely be nice to see Linux running on
that machine ;) but I should better go and work on the MVME147 port ...
https://books.google.com/books?id=cgHPkXYCnqwC&pg=PA80&lpg=PA80&…
has an announcement of the Fortune Systems "Multiplier"
with the 68010 and 68451
https://books.google.com/books?id=MdBP83DW6g4C&pg=RA1-PA78&lpg=RA1-…
mentions the DY-4 Systems Inc DSM-6816 with 68000 and 68451
at
http://comp.sys.3b1.narkive.com/olPp7IM0/fs-cosmos-cms-16-unx-vintage-unix-…
Al Kossow writes that the COSMOS CMS-16/UNX has
"a daughter card with 68000 and Motorola 68451 MMU is visible."