This took a flipping age.
Right, then, here we have it, the region we've all been waiting for: one based on the United Kingdom! Major cities are based on the largest and/or most well-known in the UK (for instance, Newcastle isn't as big as some of the others, but it's much better known).
There's a Gym for each region of England, plus one each for Scotland, Wales and Northern Ireland. Leaders are based on famous Brits past and present, bad guys are based on famous gits sadly ever present- I've tried to retain hometowns as closely as possible for the leaders.
Detailed breakdown of all the shit ya don't care about:
Shernot Forest/Robin/Bug (Sherwood Forest in Nottingham, Robin Hood, bugs live in forests...next!)
Sheffel/Sean/Steel (Sheffield, Sean Bean, Sheffield is known as the UK's Steel City)
Newcle/George/Rock (Newcastle, George Stephenson, folks from Newcastle are 'ard like a rock)
Edurg/Frank/Ice (Edinburgh, Frankie Boyle, it's awf'y cold in Scotland)
Belorn/Seamus/Fighting (Belfast, WWE Superstar Sheamus, Irish people are known to love a fight)
Manchool/Noel & John/Fire (Manchester & Liverpool combined into one, Noel Gallagher & John Lennon, fire representing the red hot rivalry Mancs and Scousers have)
Cartaff/Charlotte/Normal (Cardiff, Charlotte Church, her Pokémon mainly use sound-based attacks as Wales has given us many great singers)
Brozal/Edward/Water (Bristol, Edward "Black Beard" Teach, Bristol's success is connected to its port- and Black Beard was a pirate on the seas, so there we go)
Brove/Zoë/Electric (Brighton and Hove, Zoë Ball, Brighton has a famous amusement pier)
Isstex/Amy/Ground (Essex, Amy Childs, the East of England is known to be dry... and Amy Childs is as dumb as dirt)
Elite Four are William (Shakespeare), David (Beckham), Jeremy (Clarkson) and Joanne (JK Rowling).
And I find myself tempted to turn this into a proper game using Pokémon Essentials. Would anyone be remotely interested?