You can create the parametric objects form add menu [Shift+A] > Mesh > W_Primitives or from "Create" tab in 3D view toolbar [T].

Parameters of the object can be edited in the bottom of the mesh properties:

All properties are tied up with the mesh. So if you duplicate the object with [Alt+D] and the instances will share the same mesh, they will share the properties also.

Anytime any property is changed, the mesh is updated and all previous changes are lost. If you want to edit the mesh (as usual), use the "Convert WMesh" button.