Gen 1: Pidgeot and Aerodactyl
Gen 2: Skarmory and Crobat
Gen 3: Swellow and Salamance
Gen 4: Togekiss and Gliscor
Gen 5: Braviary and Archeops
Gen 6: Vivillion and Noivern

Gen 1: Pidgeot and Aerodactly
Gen 2: Crobat and Lugia
Gen 3: Swellow and Latios
Gen 4: Staraptor and Gliscor
Gen 5: Archeops and Hydreigon
Gen 6: Talonflame and Hawlucha

Gen 1: Pidgeot and Aerodactyl
Gen 2: Skarmory and Crobat
Gen 3: Latios and Salamence
Gen 4: Staraptor and Gliscor
Gen 5: Braivary and Archeops
Gen 6: Talonflame and Noivern

Voting is now closed as Event #3 has begun: http://gamrconnect.vgchartz.com/thread.php?id=206995

Gen 1: Arcanine and Rapidash - Arcanine is definitely good with endurance I'm just not sure about rapidash..
Gen 2: Suicune and Umbreon - I think umbreon has a good amount of stamina.
Gen 3: Swampert and Vigoroth- Vigoroth apparently doesn't get tired and he never sleeps so..... yea
Gen 4: Luxray and Lucario - I think these 2 have good endurance
Gen 5: Mienshao and Zoroak - .... idk about zoroak tbh
Gen 6: Gogoat and Pyroar - I think these 2 will do well.

Gen 1: Pikachu + Rapidash
Gen 2: Furret + Houndoom
Gen 3: Vigoroth + Blaziken
Gen 4: Lopunny + Luxray
Gen 5: Zoroak + Maractus
Gen 6: Heliolisk + Gogoat

Gen 1: Arcanine and Pikachu
Gen 2:Espeon and Umbreon
Gen 3: Vigoroth and Manetric
Gen 4: Luxray and Lucario
Gen 5: Zebstrika and Zoroark
Gen 6: Gogoat and Heliolisk

Bump (I don't want to be that guy as well.... but how do you guys see Pikachu doing well in a marathon? His short legs wouldn't help at all and pikachu doesn't even have that much endurance either)

Gen 1 Arcanine and Rapidash
Gen 2 Houndoom and Furret
Gen 3 Sceptile and Manectric
Gen 4 Infernape and Weavile
Gen 5 Keldeo and Mienshao
Gen 6 Greninja and Pyroar

Gen 1: Arcanine and Rapidash
Gen 2: Vigorith and Furret
Gen 3: Swellow and Blaziken
Gen 4: Staraptor and Lucario
Gen 5: Zebstrika and Zoroark
Gen 6: Talonflame and Greninja