To better organize our ArcSDE data, we wanted to create multiple geodatabases and multiple ArcSDE services using one PostgreSQL database cluster (a cluster containing 1 machine at this point). A side question is why can’t tables and raster be placed in Feature Datasets? This wouldn’t be an end-all solution for what we want to do but there are some messy consequences of this limitation. ESRI has instructions on Setting up multiple geodatabases in one PostgreSQL database cluster on Windows which was helpful but we repeatedly got an ‘The ArcSDE Repository was unsuccessfully completed.