Transitioning from AS400 RPG to RAD

As Chief I. T. Architect, i’m trying to build a case for transitioning away from legacy IBM AS400 traditional, top down RPG development methods to rapid application development methods using a multi-tiered architecture with an emphasis on reusable objects/components. Obviously there is resistance to this by the development group, so i’m interested in what methods other IT shops are using these days for internal development. We are a non-computer manufacturing organization, so any responses from like organizations would be of great value……..