New types of objects

Is it possible to create new types of objects (like Mesh, Text, etc) by subclassing existing ones?
I need a drawable object that would be defined and managed by few parameters (something like sphere that defined by position and radius)

In python your best bet it an empty with an object scriptlink.
The scriptlink can draw in OpenGL so irs fairly powerfill.
Properties can be stored on an object.

Interesting idea, thanks you.
And can i catch an event that user tried to switch to edit mode while this object is selected and display dialog box (or something else) to change parameters?
How can i organaize modification of such objects?