If I click the camera shutter on the remote while in Video recording, I hear the shutter sound.. but when retrieving files it seems no photo's were captured.

Am I missing something?  I think it would be a great feature in a future update if this isn't already implemented.  I know that many smart phones have this feature..

Not possible on the Spark.
Phantom 4 pro and Inspire 2 can do this.

This feature is not available for Spark.