I doubt we will (although we should), but I would make mine in that rainy marsh west of Pastoria. One thing that I didn't like about Sinnoh was that there isn't much water area. I loved how much water there was in Hoenn and even how several towns were islands.
i would make one (even though i doubt we can, but i hope) near heatrans cave, so only strong trainers (who have beat the league) can fight me )