I don't know that the term leaf cutting is wholly correct for the method Ben Lawrence describes, but it is a method I have used with good results. I have included a direct link to Ben's article below.

Here is a link that might be useful: Propagation by Leaf Cuttings

I took leaf cuttings last year, probably less then 10, But they all took. (I grew 20 plants from a combination of leaf and sprout cuttings).

I cut just below the meristem, but did not cut it in half, instead I just stripped one of the leaves off so I left the cutting with only one leaf. I dipped it in some rooting powder, and made sure the soil had "No DAMP" added to it. I stuck them into a peat pellet, then put it into a single serving yogurt container, placed that into a ziplock bag, and put them under a florescent light.

100% success.