If it is in 'just one section', then it's probably appearing rather rarely in said section. I've been snooping around the most likely places, and I've found nothing. It might be like the Potato Sack, where it was only found in Events. I haven't checked there yet, but I don't know if I can do a full scour of the place. I just hope the actual encounter rate isn't really low.
I don't have any yet, but I think I need more Pokeballs anyway. Also, 2 months on LV for me! YAAAAY *random applause in background*