The Dark Iron Entrepreneur is a level 31 speciality goods vendor located in the Dun Modr inn in the Alliance-aligned territory of the Wetlands. He is a friendly vendor in the midst of hostile level 28-30 Dark Iron Dwarves. He's a freewheeling trader.
Though not exclusively a fireworks vendor, he sells the 
[Red Fireworks Rocket] (for 1
) that the fireworks vendors sell.