Until I can get my hands on a CardDAV client application, I need to transfer my contacts from iOS or OS X to my Lumia 920.
How can I do this without uploading my contacts to Outlook/Hotmail/Gmail or anything like that?
You can use the Nokia contacts transfer app (iPhone 4 and higher) or your SIM card.
Or you will have to cave and sync them to an email account.
Source Nokia support.