Ipad4 -> lightning cck (
http://store.apple.com/us/product/MD821ZM/A/lightning-to-usb-camera-adapter?fnode=3a ) works with odacs, but you need a usb hub in the middle. The hub does not necessarily need to be powered, and I can tell you from personal experience that not all usb hubs work.
I run this setup as a bedside rig and am currently using a dlink 4 port hub (which ships with an ac adapter but doesn't need to be plugged in -
http://www.amazon.com/D-Link-Hi-Speed-4-Port-Powered-DUB-H4/dp/B00006B7DA ). Humorously, I get an error message when I plug in the odac, indicating that the device is not supported, but it works perfectly regardless. My ipad4 -> lightning cck -> ? -> odac also works perfectly (with no error message), with the usb hubs built into two of my dell monitors. It did
not work with the one usb3 hub that I tried (which I believe was made by kdLinks).
Edit: I should note that I haven't tried without a hub since the latest update. Maybe one day they'll actually revert ios to how it used to be, when they didn't run a bogus power check to keep people from easily using usb thumb drives. Then again, it's hard to sell super high capacity devises at an enormous premium if people can just carry their movies and surplus lossless audio with them on removable media.