On April 1, 2003 a Defender 3 prototype was reported to have been discovered. Sadly, little more information was forthcoming.
https://www.arcade-museum.com/game_detail.php?defender_3
SR3I9tdwolg
https://github.com/mamedev/mame/commit/3a79aca7af6e1dbce1d9f6bf66a6ad35ad23e0df
Looks like it has been dumped and is working. Guess it will be in the new release in a couple of weeks.
MAMEdev seems to think it might not have been mass-produced but only test-released in limited locations. I...
I am reminded of the old joke: A tourist in Hawaii asks a random stranger "Is it pronounced ha-WY-ee or ha-VY-ee?" The stranger says "ha-VY-ee". The tourist says "thank you." The stranger says "You're velcome".
With respect to the star cluster called "Pleiades", I've heard it pronounced by astronomers as many different ways as you can imagine. As for the video game. I swear I remember a magazine ad for it which explicitly indicated that it was pronounced "play-it-ease", but I haven't been able to find...