Hello Tom,
[I've edited the title of your topic to reflect its content, so that it's likely to attract more relevant views/replies.]
I don't think I'm aware of any CODM GUI front-end editors for the Mac platform currently. However (unless anybody else knows of one), you could probably potentially use some platform virtualisation software such as VMWare Fusion or Parallels to allow you to run the relevant Windows application on OS X.
I wouldn't imagine that CODM GUI editors would have any performance or other problems running in such environments, so it would probably be straightforward.