Here's a grab from the net showing what appears to be a factory accessory for the Flevo back to back tandem. It's a storage bag that also doubles to fair the area between the opposing seats for better aerodynamics. It looks handy. The best we can do on our bike is to hang a bag between the seats. If anyone knows about this bag or any other Flevo accessories, I'd appreciate a note from you with details.
I notice a few other differences between this Flevo and mine. First, different handlebars. Second, the rear chain reverses without pulleys. I'll have to study this one as it may be a chance to simply the drive train on my bike.