A time-limited free trial of SilverHD DRM is available for commercial users - the contact details to get a trial account are on the website. The free trial includes access to a PlayReady and Windows Media DRM license server and all the licensing related functionality that goes along with that. Disclaimer: I work for Axinom who provides the SilverHD DRM service.
Alternatively, Microsoft has a public PlayReady test server that you can use for free. Basically, it will always provide a persistent license in response to any license request made to it. Not very flexible and the URL query string customization options tend to not actually work, but maybe it suits your needs?
If you describe your needs in more detail, I might be able to offer more specific advice on how to proceed with evaluating PlayReady.