>>299955549
It varies. I've heard some people get it in as little as four weeks, and some in as many as twelve weeks. If you want it by Christmas, I'd order it now. 

Incidentally, I was also looking to order one to get by Christmas, but my main Steam account is VPN'd to Argentina. Will I be able to order an Index with an alt account, or will I have to do their authenticator to make a purchase that large?