Parameterized module idioms

[Tim Fletcher]

> The use-case for modules with parameters (if there is one) is
> where there are grounds for believing that there may need to
> be multiple distinct instances of the same module at the same
> time AND where the module parameter cascade is tolerable.

Are there any good examples of this?

What about the motivation described in Richard Carlsson's paper
(http://portal.acm.org/citation.cfm?id=940885) about callback module
usage?