I understand that a module's height is set as a "module preference" and the API says, "The users of your module cannot change these attributes." but nearly all the Google created modules have an option like "Show X Items" in the preferences. This preference doesn't only adjust the number of items seen but also the height of the module that will eventually contain them.

I would like to do the same. Does anyone know how to adjust the height of a module based on a user preference?