I have recently heard from Daxi that there is a gun that can be made using elemental fire
If any one is able to make this and is willing to do so for me i will gladly gather together the parts needed for you
and try and pay you for making it.
I can usually be found in Thunderbluff.

signed

Lighthoof
Loyal Hunter of The Draenor Vanguard

If you mean the Mithril Blunderbuss, then I can indeed craft such things.

http://www.thottbot.com/?i=7789

Given the bits I can assemble one with ease:

1 Heavy Stock (Engineering Supplies Vendor item)
2 Elemental Fire
4+3+1=8 Mithril Bars
1 Mageweave Cloth
2 Solid Stone

Just let me know; there'll be no charge given the components.

--Tinderloss