So yeah, I'm planning on doing one. I just need some help thinking up a plot. All I got down for sure is:
The region will be two small regions with 4 cities (CITIES, not towns. There will be a ton of towns, too) each, along with several island off the coasts and fly being the first HM you get as there will be a ton of traveling. To travel between both regions, you will have to go through a huge area, with a desert, wide open plains, mountains, and overpowered trainers you will need to wait until the end of the game if you want to fight them.
Also I'll need 135 total Fakemons to use, one to replace all of Hoenns. If a Fakemon you designed has an ability that doesn't exist in Gen 3, I'll have to substitute for a new one, so I'll appreciate it if more Fakemons with sprites are submitted.