Dome systems denominated as "Clamshells" have been extensively used for the deployment of small telescopes. They are characterized by small price and fast deployment time. Recently, several efforts have been spent for the design of larger clamshell domes, with the aim of adapting them to observatories hosting 4m class telescopes. This poses new design challenges, since astronomical observatories of that size are characterized by the need of several subsystems at the service of the telescope, whose characteristics barely fit with the design of existing clamshells. In this paper we present the development of newly designed clamshell dome systems, whose characteristics make them completely compliant to the requirements of high-end, conventional dome system products, in terms of sealing, HVAC conditioning, windprotection, and service cranes. We also present and discuss the results of the manufacturing and integration of the first two systems realized by EIE following such design approach, and we present possible applications to large telescopes.