More images from a recent trip to NYC. This definitely took some thought, and I have my own ideas about the intended purpose.
If it is what I think it is for, carrying a dog, I would be worried. There is an electrical cord that runs from the seat post to the front of the bike which may well be a leash.
If it is for a dog, I hope the dog is very well behaved.
Source: Bike Hacks – Mystery Bike Platform