Dragon Breath in Z axis

[brislove]

First off has there been any official ruling/faq/errata on how this works?

Secondly if there isn't anything official what makes the most sense .

If I have a dragon flying around, and it makes a blast 5 breath, is it a 5x5x5 cube? or is it some random panel in space that confines itself to 5ft squares?

I ruled that logically, like a cone it would extend up, if it starts on the ground it could be aimed up to cover a 5x5x5 area, but usually it was started on the ground, so it would only fill 2.5 (rounded down as like everything else 4e) so the breath would only fill 2 squares vertically.

So if the dragon is in the air, and shoots down, it would still be a 5x5x5 "cone"

[Eepop]

In 2D a close blast 5 is a 5x5 square that is adjacent to the character in some way.  So in 3D I would say a close blast is a 5x5x5 cube that is adjacent to the character in some way.

[Dan2]

First off has there been any official ruling/faq/errata on how this works?

Nope, not to my knowledge.

I think your method works out well, and agree that it could be reasoned that the dragon breath could fill a 5x5x5 cube.