More good/free stuff from the IBM ITSO, this time a redpaper on the System p APV Virtual I/O Server. The redpaper is some 90-pages and covers VIOS deployment examples.
Listed are some high-level architecture designs, referred to as scenarios. They show different configurations for VIOS and partitions. The scenarios described in this paper will help you derive your own implementation.
You can download the redpaper here.