This website produces religious jewelery, one of whose pieces is described as the Etz Chayim as envisaged by Abraham Abulafia, founder of the prophetic-ecstatic school of Kabbalah. Is shows a very different conceptual arrangement of Sephirot to the commonly used Tree design as developed by Rav Yitzak the Blind.
Is this design (image below) an accurate representation of Abulafia's concept of the Tree? The Sephirot appear to be ordered into four 'branches' along a series of expanding spheres; Abulafia (basing himself on the cosmology of Rambam's Moreh) did write about the cosmic spheres, however, I've yet to find anything in his writings that describes his particular conception of the Tree in detail.