Custom configuration settings?

We are an ISV and our OLAP solution will be deployed to many customers. Needless to say, various values needs to be customized to meet the client needs, e.g. KPI goal values. What will the recommended way to implement custom configuration settings in the cube that are accessable to MDX calculations?An example would be helpful. I have vague understanding of what you are asking, perhaps more explanation will make it more clear.