ah, your right, xsi is the newest. I had assumed (incorrectly) that xsi was basically Sofimage 3D just with a rewritten core.
Anyhow, I hope with zb4 we’ll be seeing a 64bit version. With Win7 users 64bit accounts for roughly half of all copies sold, so its not like 64bit is uncommon these days. Past that, they reeealy need to improve retopology, its one of the weakest aspects of zb atp. But I’m sure we’ll at least be getting better paint and something like voxels or dynamic tessellation to compete with 3DCoat/Sculptris.