FallofCamelot |
If you were going to write it then the Mana Wastes and Alkenstar would be the ideal setting.
But firearms are a very contentious issue for a lot of players and GM's. Many people do not like firearms in their fantasy so I doubt that Paizo would do an AP like this.
The point is that AP's are Paizo's bread and butter, their key income stream. That means that each AP has to appeal to as many people as possible. It also has to take into account all playstyles and character classes and a gun orientated AP would require people to play in a specific play style, one that is a niche market. It's not in Paizo's financial interest to do that and therefore I would not expect this AP anytime soon.