We now have proper Windows support in our HPC environment. Hooray? It is through pretty novel means, meant to make it as secure as possible while being easy to maintain for Linux systems administrators.
Long story short, a Windows VM is launched through Open OnDemand and starts inside of an isolated network namespace. The network namespace is started by spank_iso_netns (see below), a SPANK plugin I wrote. The user's files are made available inside the Windows VM.