With alternate Flame Breath and Cloudkill modes.
In addition to everything cool about Dragonfire Adept (from
Dragon Magic) without the bullshit dragon clause(s).
Also, needs the ability to say "Oop, looks like I have one left!" once per encounter or more, and pull out just enough small bottles to refill the power.
No class should depend on items to the extent of not working at all when said items are missing. Fighter, I'm looking at you.