Is it possible to get Microsoft PlayReady Server to output DRM'd streams that are playable by Windows Media DRM 10-PD compatible devices?
If so, where could I find any relevant documentation?
It is possible. You need to use so-called "cocktail licenses" and encrypt ASF (i.e. WMV) streams. The relevant documentation is part of the PlayReady Server documentation set, which unfortunately requires you to be a PlayReady Server licensee from Microsoft (you can become a licensee here, but it does cost quite a bit of money).