Because Service-Oriented Architectures (SOAs) usually involve different independent stakeholders, producing meaningful prototypes for validating early design ideas is a difficult task. This paper presents a Rapid Prototyping framework for SOAs built around a Model-Driven Development methodology which we use for transforming high-level specifications of an SOA into executable artefacts, both for Web Services and for autonomous agents. The framework was designed to handle a mix of new and existing services and provides facilities for simulating, logging, analysing and debugging. Our framework was validated on a real industrial electronic procurement scenario in the furniture manufacturing industry. Once input from business experts had been collected, creating the high-level PIM4SOA (Platform Independent Model for SOA) model, deriving the Web service description and incorporating existing Web services took less than a day for a person already familiar with the techniques and tools involved. We show that rapid prototyping of SOAs is possible without sacrificing the alignment of the prototype with high-level architectural constraints.