I know the real Wyatt Earp wasn't anything like the yarns folks have spun about him and quite frankly, I don't care. A good story is a good story. As long as you acknowledge that it's made up, it's okay.
If you can't tell from the picture accompanying this post, Tombstone is my favourite version of Earp. Heck it's my favourite western (along with another amazing Kurt Russell western, Bone Tomahawk).
If you want to add Tombstone's lawman to your game, here are Six-Shooter & Wagons stats for the marshal.
Level 7 Soldier
Str 13 Int 10
Dex 16 (+1) Wis 15 (+1)
7 HD (36 HP) Save:10 Movement: 12
AC 8  (Dex)
Attacks: Pistol (+7 to hit, 1d6 dmg, 60' range) or Rifle (+7, 1d6, 120' range) Shotgun (+7, 1d6+2, 25' range) or Knife (+6, 1d6 damage)
Other: 7 attacks a round against foes of 1 HD or fewer, +1 save vs. death and poison, no penalty for fighting from horseback. 1 chance on a 1d6 to track foes in wilderness, 1-2 chance to hunt/forage for food in the wilderness, 1-2 chance on 1d6 to administer first aid
Equipment: Marshall badge, horse, pistol, shotgun, rifle, knife, 20' rope