I'm actually sort of surprised that there isn't an integrated technique for backing up projects and media. Seems like that would certainly be on the "A-List" of features.
With FCP7 I've always used a very basic app to clone my projects called SyncTwoFolders.
http://tcfj.pagesperso-orange.fr/site/ind_JS.html?Prg_S.html&Prg_AutresRB.html
What I do with FCP7 is I create my scratch folder on the root of my main drive called FCP which contains all of the capture, renders, etc.
I have another folder at the root which contains my actual project files and random media.
After I capture my footage I drag both folders to my backup drive. From that point on I simply use SyncTwoFolders to update the FCP back-up when ever I want - usually the end of the day. I use the finder to copy my projects. If I'm working several projects or add random media, I'll use SyncTwoFolders to do the projects folder as well. My autosave vault is on my system drive. I don't leave my BU drive mounted while I'm working.
If something happens to my main drive I jus mount my backup drive and continue working. Renders and all.
I'm hoping that this same technique can be employed for FCPX.
If this does work out I encourage you to donate something for this shareware. It really is just the right amount of features without getting too cumbersome. Very cool.
I know there's no autosave vault or "save as" or even "save" anymore, Reason?… unknown.
So, with the well documented Self-Save Bug looming any sort of cloning might be pointless since you might be cloning a project that has lapsed into a coma and is no longer performing it's self-update tasks.
I'm waiting til that one has been sorted out before I buy FCPX.
onward...