Software product lines have already proven to be a successful methodology for building and maintaining a collection of similar software products, based on a common architecture. However, when the base system is heterogeneous and extremely large in size, an extra level of complexity is introduced that should be addressed with appropriate methods and techniques. A good example of this kind of systems is the product family composed by the software distributions composed by libre (free, opensource) software, and based on Linux or BSD kernels. All of them can be considered as a part of a product line, based on a large collection of thousands of packages. One of the main problems faced by these distributions is the increasingly growing number of dependencies among packages, which is already caused problems, with a high risk of rendering the management of such large distributions impossible. In this paper we address some of challenges and main problems of Linux distributions when adopting a product line approach, with special focus to the maintenance and evolution of such systems.