I think there are plans to add more streets to Aranna and Callopee too. I have been to all the streets in both places but have yet to receive Completist badges for them. Their badges in the Encyclopedia show "thumbs up" pics instead of the other type of completist badge pictures.
I got Callopee too, so it is possible! Aranna, though, is not...I agree is that it's probably b/c it's 'unimagined territory' that we cannot earn the badge yet. Gook luck!