Mechatronic products combine hardware and software; and today, much of software engineering is directly or indirectly involved to support mechatronic design. Due to the high level of standardization, especially among its hardware, the design of mechatronic products is strongly characterized by integrating standardized components and thus seems an ideal environment for product line engineering techniques, which allow dealing with the variability of reusable components if fully definable a priori. However, while many aspects of mechatronic design are standardized, there is also the need for the continuous construction of new components. However, today, it is difficult to seamlessly integrate the reuse of standardized components with the development of new components. This article presents a model-based approach for integrating component variants with user-defined components to better support the mechatronic design process. We present a combination of existing approaches addressing certain needs of the mechatronic design domain, for example, the integration of components is ensured through incremental consistency checking. Our approach is illustrated using the example of a basic articulated robot.