Panasonic have a twin-camera setup called the W850 / W858 / W850M, and it features dual camera system for users to enjoy picture-in-picture recording.
Not only high image quality which is realized by new Crystal Engine Pro+ and advanced Level Shot function/5 -axis hand shake correction, these camcorders also comes with Wi-Fi/NFC to expand shooting experience even further.
(The W850M and W858 are the sister models to the W850, which have same level of image quality.)
Please see Panasonic for more information about their twin camera camcorders.