Keezer Question

So Ive been looking into building a keezer. I'm going to do a 8" collar. But to be different I want to affix the taps to 4" copper pipe. this would bring the taps off the wooden collar I will also put a Y fitting on the ends inside the freezer. one side will run the beer lines into the copper and the other I will affix a computer fan. will the curvature of the pipe affect the seat of the taps and does anyone know a place to source 4" copper pipe

if you get shanks meant for a tower, they're curved to seat flush against it.
You could use standard shanks though, but I think the looseness of them may bug you.
They shouldn't leak though...

4" copper may be found at your local Ferguson. I'd call and ask first though. Looks like there's three of them in Stockton.
http://ferguson.com/static.pl?S=locations_main#search?address=stockton%2CCA&radius=15