Al, stay away from galvanized and life fire. Bad combination.
The fire actually doesnt have to be at the temps that melt or burn off tha galvanized layer to get some nasty stuff on your food and in the air that you breath while cooking.
http://en.wikipedia.org/wiki/Zinc#Precautions
Did you check scrapyards, natural gas and water supply companys, pipeline builder etc. for pipe ?
I paid 5 € for the pipe that i used for my smoker
DM