I think you should get a kitty for Luna. Cats work out their own rules to have their "alone" time, such as hanging out in different rooms or napping at different times, but they do seem to enjoy having thier own kind to be with.

Also, think of how much worse cat over-population would be if we restricted ourselves to just one cat per household .

I'm sure that an only cat, just like an only child, reeps certain benefits from getting undivided attention, but since you mentioned that Luna likes other kitties, I think it would be a great idea to get her a friend.

of course you know the rules, once you do - we will want pics and updates