Those aren't bibs on the Dyna. That is a filler piece to cover the frame, filler, and electronics in between the two tanks.
I have never seen anything like that available for a single tank. Not saying that there isn't anything out there, but I've not seen it. You can, however, convert your Sportster to the Dyna fat bobs with the guage and filler.
i new the Dynas was the tank split, i just like the look of it. thing it would look good on the nightster. i don't like the Mustang ones, had one on a previous bike. guess i will stick without one.