Nokia Power Ranger phone is concept phone or rumour? Dual-boot phone.. Runs on OS WP8.1 and Android Kitkat.. And more details in below link
Nokia Power Ranger is a Dual Boot Smartphone With Android 4.4 KitKat and Windows Phone 8.1 | Concept Phones
Nokia Power Ranger is a Dual Boot Smartphone With Android 4.4 KitKat and Windows Phone 8.1 | Concept Phones