This paper presents a method and concepts of a supporting tool for really rapid prototyping of large-scale business information systems. Our method is based on the following guidelines: (1) small team of highly skilled members with combined skills, (2) prototype-based development of subsystems and the system as a whole, (3) brainstorming sessions always involving system analysts, database and application designers, and user representatives (if needed), and (4) development tools providing for efficient prototype development by maximum automation of all design phases. The also presented development tool is based on standardization of functional and visual characteristics of an application, a library of high-level, coarse-grained components, and a set of rules for model-to-application mapping enabling automatic application reconfiguration in case of changes in the data model.