Might look into a lubbocki? Lot of color in a little (inexpensive) fish. I have an exquisite on the way for Monday:C Rubeus is definitely an interesting looking fish, but there's already enough red in the tank (especially with other items on the stocking list) that the addition of other colors (or a fish with a blend of colors) seems like a more appealing option to me.
Good note about the Naoko, I'll keep this in mind. I like to keep the peace in my tanks, even if that means severely understocking. I do build my scapes around habitats, even if it means less room to mount coral or less viewing angles. IMO it's only right to build a satisfactory home for the fish as the primary consideration, with coral as a means to "fill in" - but I know not everyone agrees with this perspective.
My goby is an absolute menace with the sand - I'm convinced he hates my zoas. In my barebottom holding tank with just a takeout container of sand for the goby I have watched him pick up a mouthful of sand and swim 2' to the other side of the tank just to deposit it on a zoa colony, then turn and stare at me through the glass. Cheeky little guy he is.