I am playing Borderlands and I'm in Concodria looking at town square, and there is no shift kiosk for me. Is it because I am only level 7, or because I am on a Mac?
I don't believe there's a level requirement; I've reached Concordia pretty early and still seen the kiosk.
Make sure you're looking in the right place. This question is related, and the answer I posted there includes a screenshot showing the kiosk's location.