OK, so I needed a follow focus and got an older but perfectly working Arri FF2.

Problem: my 15mm rods are "lightweight" (video) standard for intracenter distance of 60mm, while FF2 was designed for "studio" standard of 100mm intracenter.

So I bit the bullet and did a mod. Sawed off the lower part, reinforced the top part with two bolts, and used JB Weld compound to "cold weld" it to some Cavision video rail block.

Result is one great working FF (may look a bit odd from behind the rig. Is that chewing gum holding it together?? LOL :)