Yes, you can sculpt with polymer clays!!
Sculpting with polymer clays is nice because you can
sculpt right in color, instead of painting the item, as the
clay itself is colored! There are some artists that sculpt
in a base white and paint it later, but most just use the
color clay they need and sculpt with that.
 
I am not much of a sculptor, unless you count my dragons,
which I consider more 'modeling' than sculpting. I don't know
a lot about sculpting, but I will provide some links, as I can,
to some really nice sites of people who DO sculpt with polymer clay.
 
As for my 'modeling' I do have a few things I have made,
besides my dragons, and will share the pictures with you.
 

BabiesSome little babies. These are under 2 inches tall.

Bunnies
Some rabbits.

Horses
Horses...I like these little guys, hehe.


A little girl, puppy, and a teddy bear.


A seal, turtle, and penquin.


A goldfish, pig, and little ghost.