No idea if this has been posted before, but I saw a really interesting setup for Leafs the other day while searching around Pirate.
Essentially it's a Uniball mounted to the bottom of the leaf. It obviously offers a lot more flex, at the expense of keeping body roll to a minimum. Not sure how I feel on it. It obviously is something you don't want for on-road use (with body roll), but for a trail rig it'll help a leaf spring setup flex a bit more.