I frequently create modules containing several related packages/classes. Most often they are a main class and a number of helper classes, although sometimes I provide a base class and various derived classes that way too. The main class/package is the module name and the derived/helper classes are either not used outside the module, or (in the case of subclasses) are available just by virtue of using the module containing the base class.
Note that Perl doesn't really provide 'classes', it provides packages which can generally be thought of as classes.
True laziness is hard work