I know that Cobb makes a short shift plate, I didn't know they made an arm. Of course Breedt definitely makes an arm.
If you are interested in a short shift plate , I do have a used (about 6 months) Boomba short shift plate that I'm willing to part with. I recently switched to the JBR shift arm. On top of that, I also have the JBR transmission side bushings, which are brand new. I bought them by accident when I bought the arm and forgot that I already installed the Boomba ones which are very similar.
If you want the used Boomba plate (with all necessary hardware) and the new JBR transmission bushings let me know.