I don't know of any such thing. Can you not speak with the SP administrator to see if you can get a concession for making workflows. At my client, we plan to lock down SPD, too, because it's dangerous in the wrong hands. However, we will have a special server for doing SPD changes limited to certain people, and we will require them to first build in a test/pilot environment. They can't make it where NO ONE can use SPD, else they are severely limiting the functionality of SP.
Are you at a National Lab or Battelle by chance?