Seen in Okinawa Japan at a local sporting goods store. The bike is called a Ringwood.
It has two frame posts and the area between them is used with a heavy cloth shaped into a storage compartment.
I'm sure this has been done before as I know nothing is ever really new in the bike world but it's new to me.
I pulled one of them out and sized it up and it's pretty small. Too small for me. I'm guessing they cater to little old Japanese ladies or something with this bike. Still it's cool and worth a look.
John