I was with the project in the early days and do desktop backgrounds and login sounds. Here's a desktop I like (here's a preview and a link below to the HD file):
There are several more here:
I'm still working to get the default but no luck yet (some of those shared are misses, but my art professor always said, you can't judge your own work so enjoy!).
Let me know what you think or make some requests in this thread if you like.