Curved objects - how?

I've tried making a few objects and I have to say that the 2L builtin tools are surprisingly good -- but the basic shapes are too limited. One hugely important class of geometric solids is missing: curved things!

This all started when I thought, hmm, wonder if I can do a Fred Astair AV? Could make a tux with the clothing templates, ok... cane, ok... shoes with spats, hmm, maybe... but the TOP HAT?!?!

A plain "stovepipe" like Abe Lincoln wore could be made from a tube and a disc, but a real Fred Astaire, man-about-manhattan, top hat is curved two ways. The body is a rotated, shallow parabola; and the brim is a warped disk. And that's two shapes the 2L tools won't make, AFAIK.

This must apply to lots of other possible hats, and other things (musical instruments?) So what do people do? Are there third party programs to use, then upload objects? Or is that possible?

ML

The body part could be made using a torii, hollowed and cut with the advanced cut option. The brim - possibly a hollowed, dimpled sphere? Failing that you'd have to model it using several different shapes, objects attached to avatars don't count against land prim limits so go wild