The new release of GeoServer+WCS is capable to render rasters by WMS requests.
The link "getMap" under the myWCS title in the welcome page shows a
request with two layers, one raster and one geometric.
This is a very first version ... I need help to handle the SLD
RasterSimbolizers.
Notice that if you want to recompile Geotools packages, first you have
to patch them in order to allow the WCS to work correctly.
Best regards,
Alessio.