Just an update...
I called JR Americas and spoke with a gentleman named Chris.
I asked about the Prometheus Biplane, as there is no ETA or date on the site, just backordered (which has been this way for almost a year now)
He said that due to the size and cost of shipping F3A planes, they currently have no incoming shipments (they are waiting for the factory to ship their next container for winter 2018 delivery ... no Prometheus monoplane or biplane planned in that shipment)
I was a bit surprised, but maybe they will no longer be shipping or carrying the "Giant" Sebart aircraft planes either ... they have to be bigger than a 2m plane.
Seems like a nice looking plane that never went anywhere...
Also, here is a YT video of the airplane flying with a C54 (non Contra) setup