Microkernels are an intriguing technology for operating systems research in general and for real-time systems in particular. To gain experience and to explore new ground, the OS research group at Technische Universit\"at Dresden has been developing L4/Fiasco, a real-time implementation of the L4 microkernel specification. Using this kernel, we built an architecture that supports legacy software and provides real-time guarantees. In this paper, we will describe and discuss the design decisions that led us to this architecture. Based on this system, we set out to explore interesting real-time research areas such as networking, disk scheduling and real-time graphics. The results have been published separately, but we will use this article to give a concise overview and present the rationale of our platform strategy as a whole.