Do you have .QTZ files you want to use as your Desktop? There's a nifty little app that allows you to use any Quartz Composition files as your background in OS X. It is called Quartz Desktop. You can use any resident Quartz files, or download many others from other sources on the web. For example, "Quartz Compositions" is a good web-based source.
This version of Quartz Desktop is compiled as a universal binary.