This project takes the last non native cardboard vr sdk, gvr .85 and incorporates it with apple's AR kit allowing a user to toggle between both handheld and headset VR displays
Instalation Guide unity 5.6.1 p 1 The only thing you need to do in unity is to uncompress ARKit-Cardboard-VR/ARKITCardboard/Assets/Plugins/iOS/libgvrunity.a.zip as it's too big for git.
Setup your dev enviorment for Apple Iphone AR Kit, https://forum.unity3d.com/threads/arkit-support-for-ios-via-unity-arkit-plugin.474385/ The basis includes ios 11, xcode 9 beta 2,
ToDo
-Fix distortion issues on hmd ar mode
-Allow for easier mode managament.
-Get raycast hooked up to the proper cameras when switching.
-Fix the temporary vr camera switching issue that causes the stuttering.