When I was packaging beer in 22 oz bottles, I purchased them from Ryco Packaging in Denver. There was a minimum of 5 pallets. That was roughly 2500 bottles. Double that for 12 oz.
Manufacturers are Ball-Foster Glass Container and California Glass. When you are ready to buy a couple of container loads at a crack, you can get your own design, like New Belgium.
Crosby & Baker and the other homebrew store distributors also sell them with a lower minimum but higher cost.