Software product families are a means for increasing the efficiency of software development. We propose a conceptualisation for modelling the evolution and variability of configurable software product families. We describe a first prototype of an intelligent tool that allows modelling a software product family on the basis of the conceptualisation and supports the user in interactively producing correct configurations with respect to the model. The implementation is based on an existing general purpose configurator and thus is not application domain specific. We use the Debian Familiar Linux package configuration task over many releases and package versions as an example. Preliminary results show that the conceptualisation can be used to model evolution of such a software product family relatively easily and the implementation performs acceptably.