Tandem Trike with 5 wheels

[Jfreewheel]

We have a homebuilder who sent us picts of a tandem trike with 5 wheels.
Regular 3 wheel configuration for the captain, BUT a detachable stoker
attachment with 2 wheels. It's like those ki's bike attachments. Picts at
http://www.gaerlan.com/bikeparts/frame/tips/tips.html