This article presents the design and pilot implementation of a suite of intelligent methods, algorithms, and tools for federating heterogeneous experimental platforms (domains) toward a holistic Future Internet experimentation ecosystem. The proposed framework developed within the NOVI research and experimentation European collaborative effort, aims at providing a modular data, control, and management plane architecture that includes: an information model capturing the abstractions of virtualized resources residing in different yet interworking experimental platforms; resource mapping algorithms tackling the inter-domain virtual network embedding problem; mechanisms providing interoperability of monitoring tools; policy-based management services for role-based intra and inter-domain management policies; and dataplane stitching mechanisms to enable the composition of user-specific slices (baskets of virtual resources drawn from the federated substrate). The NOVI framework was deployed and validated in a combined testbed consisting of two dissimilar platforms: a private PlanetLab domain with resources interconnected over the public Internet; and FEDERICA, an infrastructure of virtual resources interconnected via dedicated networking facilities of European National Research and Education Networks and GEANT. This pre-normative work is expected to contribute to bridging Future Internet experimental federations with interconnected cloud architectures and interworked public/private data-centers, adding value via its intelligent services, information models, and composite algorithms.