I should be continuing with the Cocoa port of AC3D, but this was more fun...
Try this plugin (Windows AC3D 7.5.02 only) - put the spherize.p in the plugins folder and it will add a "Spherize vertices" item to the main tools menu:
www.inivis.com/external/spherizeWIN7502.zip
Try it on any Block and you'll have your quad sphere
.
Also try selecting parts of objects, multiple objects or perhaps a sphere and a single vertex outside it - you can get some great distortion. Can also be used to make round holes in objects.
Please let me know if it works, I think this would be useful for others.