Zoom's H3-VR is designed to record 360 surround sound directly onto the SD card. It has four microphones in an Ambisonics arrangement attached right to a recorder running on double-a batteries and recording to an SD card.
Recordings can be converted into Ambisonics B format for 360 format, or used in Unity Game Engine for VR. H3-VR also can record in binaural format too.
Available now priced at $350