Well thats the problem with it, I'll admit its interesting, but it just being a 2 seater will kill off most interest from your avg Car buyer...just look at what happened to two door SUV's in the 1990's...they where nearly all gone by the end of the decade. The car is Practical, yet very unpractical at the same time. I think the loss of any rear seating isn't off set by a having a bed in the back.
If they can sell 10-15K of them of a year...you might consider it succesful, but otherwise I wouldn't.