I definitely think this pack is coming, but I don't think it's the next GP. First because I think this would be an EP (and the survey itself suggested that), and second because this is not a major first. Also, the survey was pretty recent, so, considering how long it takes to make a pack, I don't think it's coming around by october.
My guess is it will be EP10, and it will come in november/december.
Hopefully it is actualy a VACATION pack, and not some adventure (I love JA, but it's not a vacation pack). And hopefully it will add hotels.