Ive built my own adapter for the Samsung Gear 360. Now it fits the standard "DJI Osmo Mobile" Gimbal nicely. The whole setup is pretty small and works okay. Take a look at my first test videos. Should work with other small gimbals too.
PS. What we really need is some sort of RAW hack for the Samsung Gear 360 to get native image quality out of the sensors without the codec compression. The H265 codec is somewhat crappy if you have small details everything gets mushy. I've made some intense tests and the best quality I get from the RAW files is through the Samsung S7 or the paid version of AutoPanoVideoPro with ProRes output.