The thinking behind each design.....
Kanto - It's Mt. Moon at night.
Johto - Bell Tower with Mt. Silver in the background.
Hoenn - Sky Pillar in Hoenn
Sinnoh - Spear Pillar ruins in front of Mt. Coronet
Unova - Black City and White Forest
Kalos - The Eiffel Tower look alike in Lumiose City. (Fun Fact I have climbed the real Eiffel Tower before)
If you want these badge designs to appear at an artist alley start commenting please so I can gauge demand/popularity please!