I'm unaware of any other seats that are a direct swap onto a KZ1300.
The seat from an A series KZ1300 is not a direct bolt on for your B series.
The upper rear portion of the B2 frame is different from the A series. The seat mounting brackets are different. Also, the B frame has no rear turn signal mounts and no mounts for the tail light.
That said, people have converted B's to A configuration. I do not know exactly how the A seat was mounted onto the B2. I plan to install an A seat on my B2 in the near future, so maybe I'll find out.
You might consider cutting the raised vertical back off the B2 seat and having it recovered.
