For my upcoming RotRL game, one of my players wants to play a gunslinger musket master who also has a hound companion. Other than levels in cavalier (mounts only), nature cleric/druid (not a nature loving character), and ranger (too ineffective of a companion for multiclassing), there were no ways to accomplish this. So, we made an archetype (thanks to Epic Meepo for the formatting and Paizo for the Cavalier mount description that this was ripped from):
— Alkenstar Houndmaster —
Replaces: deeds (gunslinger's initiative, startling shot), nimble
Alkenstar Houndmasters hunt their foes with a gun in one hand, and the other hand resting on their faithful companion.
Just A Man and His Dog (Ex): You gain the service of a canine to fight and travel with. This creature functions as a druid's animal companion, using the houndmaster's level as his effective druid level. The companion must be a Dog or Wolf. The GM might approve other animals as suitable mounts.
The companion is always considered combat trained and begins play with Light Armor Proficiency as a bonus feat. A houndmaster's companion does not gain the share spells special ability.
A houndmaster's bond with his companion is strong, with the pair learning to anticipate each other's moods and moves. Should a houndmaster's companion die, the houndmaster may find another dog or wolf to serve him after 1 week of mourning. This new companion does not gain the link, evasion, devotion, or improved evasion special abilities until the next time the houndmaster gains a level.