It's done! FME 2013 Beta reads and writes rasters from and to PostGIS! Safe Software posted a short tutorial in YouTube at the beginning of the month explaining how to write rasters into PostGIS and how to read them back using FME Workbench. There is no option to tile the raster before loading it because FME provides another tool, the "RasterTiler" transformer, to tile a raster source before feeding the PostGIS Writer.
