If this back comes in at the same price or lower than the X camera, then I will for sure buy it. For me the form factor and size of the old V series is just perfect. I can press my old V gear into service again. That would make me happy.
I understand that some of the comments that it will have limited use and not versatile, etc. I have yet to meet a pro shooter in my years of shooting that had just one system or a carpenter that had just one saw.