This paper discusses how Systems of Systems (SoS) can be constructed by linking together embedded computers in constituent systems to create complex but more flexible and adaptable systems. The approach of software system development is called Federated Embedded Systems (FES) and their revolved ecosystem of players is presented, aiming to ensure quality in engineering SoS. Ecosystems for Federated Embedded Systems (EcoFES) comprise a new area of research that scales component-based software development for embedded software into new dimensions. The proposed ecosystem dimension introduces an open, flexible and adaptable SoS architecture for improving the process of FES development. In the paper, we identify some architectural challenges and discuss the implications of scaling from a closed ecosystem to an open one, providing open collaboration and innovation in the context of FES.