At Rill & Decker Architects we run ArchiCAD on Mac OS X. If you work at Rill & Decker, this is your stuff. If you don't, but you work in ArchiCAD, you may find something interesting. Anybody else, I don't know.
Since I've needed a silo top object one time in ten years, there's a chance that among a group of people larger than just me someone will need a silo top object at least one time in the next ten.