Recently, systems providing access to extremely large data collections, managed in a distributed manner, gain emerging attention. A promising approach to implement the physical layer of such systems are structured overlays based on the peer-to-peer paradigm. On the level of query expressiveness, ranking queries like skyline queries are predestinated for providing a fast but concise overview of the data. The problem is that structured overlays are able to handle dynamic and unreliable environments, but usually support only limited query processing capabilities, which are very improper for processing such sophisticated queries. In this work, we propose three variants of a skyline operator and two extensions, especially suitable for efficient determination of skylines in the before mentioned overlay systems. Additionally, we back the introduced approaches on an appropriate cost model, ready for implementing adaptive costbased query optimization.