By far the closest thing to a pullover machine is to use ab straps attached to a high pulley, lie on a bench with the straps attached to a medium or low pulley or attach them to a chin up bar and pull up lifting with the elbows.
This takes the secondary muscles like tris out of the equation. Straight arm standing pulldown-type motions using a lat bar are fairly good but still involve other secondary muscles such as tris & forearms.