In service-oriented Grid computing, great emphasis is placed on platform independence and cross-platform interoperability, at the price of a performance overhead incurred by the middleware and the high level programming languages typically utilized for developing software services. Reconfigurable hardware has been used in many areas of computing to improve the performance of applications by realizing performance critical parts in hardware. Typically, this is done in an application specific way, creating a custom solution for the project at hand for a specific reconfigurable hardware system. In this paper, we introduce a generic architecture in which Grid services can be dynamically transformed and run on reconfigurable hardware in a dynamic environment in which different types of reconfigurable hardware systems are present. Three approaches - static design time integration, dynamic run time integration and transparent dynamic run time integration - are presented for integrating such on-demand "hardware services" into a service-oriented Grid environment.