NOTE: Pylo has been retired in favor of PyVisfile.
Pylo supports the majority of datatypes allowed in Silo files, such as unstructured and rectangular structured meshes, particle meshes, as well as scalar and vector variables on them. In addition, Pylo supports expressions of scalar variables and semi-automatic writing of parallelization-segmented Silo files.
Pylo has a manual that also contains installation instructions.
Examples of visualizations resulting from files written by Pylo can be seen on my resarch gallery page.