Fake Edit: Do what Bifuu has said. This is just my suggestions on how to do it, not involving admins. I wrote this before Bifuu posted, but didn't press Reply until after he replied.
You can put your project to the Deleted stage of development to "delete" it.
To do this, go to your project. Click on Project Management and then on Edit Project. Scroll to the very bottom of the page and change the Development stage to "Deleted". Then your project should be deleted!
The project will still be "there" however (at least I think it will be, tell me if I'm wrong) so to eliminate all traces of your project, simply merge two projects together (this one and another one) . Then when your merging them together, keep only the information on your non-deleting project. Double check to make sure all fields are pointing at your second project, not the one your deleting. Then merge them and boom! Your project should be completely gone. That's what I did for one of mine.