> You might want to look into the "Dragonborn of Bahamut" in Races of the Dragons. You start as a regular character, and hear a call from Bahamut (usually around adolescence) and are asked if they want to devote their life to her. If they accept, then they construct a ritualistic egg and sleep in it for a night. Afterwards, they emerge as a Dragonborn.
For stats, a lot of your racial bonuses and features change. Ant classes you have remain the same. You can choose to get stuff like wings or a breath attack, and the book includes Dragonborn specific feats you can take.