Last month, someone asked about streaming two THETAs from Windows 10 using the software driver. I was not able to get this to work on OBS.
In my first test, OBS does detect two THETA V cameras. However, it only shows one RICOH THETA V 4K device. it might be possible to get this to work with a MacOS device or with a Windows 10 application that can use the RICOH THETA V device.
Update: 11/2/2018
Could not get to work in limited tests with MPC-HC on Windows 10 and also on Mac.
If someone gets two cameras working, please post test results.