Support of end-to-end Quality-of-Service (QoS) and ate high-level programming abstractions are two crucial factors for the development of future telecommunication services and distributed multimedia systems. Todays middleware systems, like the Common Object Request Broker Architecture (CORBA), support high-level ing abstractions, but they do not appropriately support the demands from soft realtime and multimedia applications. We develop a flexible and adaptable middleware that supports a broad range of QoS requirements of distributed multimedia applications. In this paper, we present design, implementation, and preliminary performance evaluation of our first prototype. We have extended the object and message layer of the CORBA implementation COOL with QoS support by (1) enabling QoS specifications for method invocations, (2) integrating bilateral QoS negotiation between client and server, and (3) implementing a simple unilateral QoS negotiation between message layer and transport l...