If you were playing in Level Up, you would pick the Dragonborn heritage with it's breath weapon trait (which is a common trait held by all Dragonborn in Level Up) and then pick up a Halfling gift at 1st level. Level Up offers up these Halfling Gifts: Burrowing Claws (Burrow speed, 1d4 + STR bonus natural weapons), Tuft Feet (expertise die on checks and saving throws against being knocked prone, and Thick Soles which would give you immunity to sharp terrain hazards like caltrops) and Twilight-Touched (Darkvision and Telepathy). Unfortunately, Halflings receive Increased Luck at 10th level as a Paragon gift, so you can't be lucky.
Or you could pick the Halfling heritage and pick up a Dragonborn gift (Draconic Armor, Draconic Fins or Draconic Flight), but you wouldn't have access to a Dragonborn's breath weapon.