Could most of the process that you described be gathered inside a Custom Action?
I mean: setting the render size, removing the lights, positioning the cam, setting the background and launching the render!
How would the script know where to position the camera? A small item will need you to zoom or move the camera right up to it, a larger one will need you to back the camera away, an unusually shaped one may need you to shoot it from a specific angle.
Easiest way to do this may be with a saved scene that you use specifically for this kind of thing - merge in your new object, change the camera position if necessary, set the render size, shoot.