The dragonborn, as a player character race, is typically looked upon with scorn throughout the OSR. It's not a traditional fantasy race and has little if any precedent in the literature the game derives its roots from. I remember my first exposure to a "dragon-man" PC race was in the "Council of Wyrms" campaign setting, which included an optional half-dragon PC race. I own the box set but never had the chance to run it (though that may be a future M74 conversion, who knows), but even reading through it I found the half-dragon concept to be a bit silly and contrived, even in the midst of a campaign setting where players could literally play as dragons.
Regardless of all that, Type-IV D&D includes, in its first Player's Handbook, the Dragonborn as a PC race. The history of the implied setting is filled with references to an ancient Dragonborn Empire called Arkhosia. Even the venerable Forgotten Realms campaign setting managed to find a way to write these Dragonborn into its most recent iteration.
I'm not a huge fan of the Dragonborn by any stretch of the imagination, but my kids think they're awesome. Castle Ravenloft and Wrath of Ashardalon board games each came with a Dragonborn hero to play, so I have a couple miniatures, one wizard and one fighter.
Aside from their draconic appearance, their iconic ability is a breath weapon of some sort. Type IV D&D offers the following options: acid, cold, fire, lightning and poison. This must be selected at character creation and cannot be changed.
I want to avoid any of the once-per-encounter silliness that is part-and-parcel of the Type-IV experience. The way to do this well with Microlite seems to lie with the spending of hit points to use such an ability. I would have to equate this ability to at least a second-level wizard spell.
Dragonborn get +2 to STR. Experience base modifier of +7. Special Abilities: at character generation, choose fire, ice, or lightning as your breath weapon. Fire can strike up to four creatures in a small group within 30 feet for 1d8+level fire damage. Ice can strike up to four creatures within 15 feet of you for 1d8+level cold damage. Lightning can strike up to four creatures in a straight line from you within 30 feet, for 1d8+level lightning damage. Use of this ability requires a ranged attack roll vs AC and costs 3 Hit Points. Dragonborn also recieve a +4 bonus to saving throws against damage/attacks that are similar to their breath weapon type.