Virtual platforms are widely used for system-level modeling, design and simulation. In this paper, we propose a virtual platform-based, top-down, system-level design methodology for developing and testing hardware/software right from the concept level and even before the architecture is finalized. The methodology is based on using tools such as QEMU, SystemC and TLM2.0 that starts with a functional, high-level description of the system and gradually refines the intricate architectural details. We present our results by testing a novel concept aimed at performing audio blogging. The system under consideration involves the design of a low-power wearable audio recorder, an Android application for user interface and a server for audio analysis. A virtual system consisting of three instances of QEMU and other tools was created to demonstrate the concept and to test this approach. Finally, we describe a suite of tools useful for quickly validating concepts and creating virtual platforms for early hardware/software codesign.