We introduce an open framework for built-in accessibility support at all stages of product development based on the Virtual User Model concept. The goal is to introduce simulation-based and VR testing into the automotive, smart living spaces, workplace, infotainment and personal healthcare applications areas. Our framework also aims to ensure that future products and services are being systematically designed for all people including those with functional limitations. An open simulation platform parted of several tools provides automatic simulation feedback and reporting for guideline/methodologies compliance and quality of service. To achieve this objective, detailed virtual user physical, cognitive, behavioral and psychological models as well as the corresponding simulation models have been integrated to support simulation and testing at all stages of product planning and development.