MM 68
Quote:
"True dragons are winged, reptilelike creatures of ancient lineage. They are known and feared for their size, physical prowess, and magical abilities. The oldest dragons are among the most powerful creatures in the world."
"The known varieties of true dragons (as opposed to other creatures that have the dragon type) fall into two broad categories: chromatic and metallic..."
"All true dragons gain more abilities and greater power as they age (Other creatures that have the dragon type do not). They range in length from several feat upon hatching to more than 100 feet after attaining the status of great wyrm. The size of a partocular dragon varies according to age and variety."
Draconomicon 4
Quote:
"For the most part, this book concerns itself with the ten varieties of true dragon described in the Monster Manual...True dragons are those creatures that become more powerful as they grow older."
"A number of other true dragons are described in Chapter 4 of this book. In addition, Appendix 2: Index of Dragons provides a complete list of all true dragons that have been presented in official sources."
Note: Kobolds were published well before the Draconomicon, and do not appear on the list of True Dragons, nor even the list of Lesser Dragons.
In fairness, also note: Draconomicon is (C) 2003, Races of the Dragon, where they talk about Dragonwrought Kobolds and Kobolds considering themselves as having "age categories", is (C) 2006.
Kobolds are explicitly called out as "Dragonkind" (Races of the Dragon p4), but so too are numerous creatures from both the True Dragon and Lesser Dragon list.
One could argue (several have) that since they describe themselves as having 12 age categories, and suffer no age penalties to Str/Dex/Con, they become "more powerful as they get older", and thus count as True Dragons.
Others would argue that they fail the other criterian later in the description. They're not "feared for their size and physical prowess", they don't "range in length from several feet upon hatching" (in fact, even adult Kobolds aren't "several" feet long, they can't even manage 3') and certainly aren't "more than 100 feet after attaining the status of great wyrm".
So yes, I'd say there is solid evidence of "True Dragon" as a game term, and enough of a definition to be able to string together a good idea of what it means. And, Kobold delusions aside, I don't think that definition has any room in it for a kobold with one feat.