I would have to agree that the least owwned pomacanthid is Centropyge narcosis. I have never even heard of fanciers discussing this species.
Within the last few years I have seen 3-4 hot tomatoes (hotumatua), 2 clippertons, several clarions, several army tags (Apolemichthys armiatagei Hybrid between A. trimaculatus and A. xanthotis), plenty of interruptus, personatus, joculators, conspics and other Chaetodontoplus species.
What I havent seen is debelius, nahackyi, kingi or guezi. The clippertons i saw were the result of a hit and run job which bagged about 50 specimens. I am pretty certain the hawaiian specimen originated from this same collection.