"...then go grab the untouched raw version off another drive."
Derrick, I'm not sure whether you're aware of this feature or not. Under File in iPhoto's menubar there is an option called Revert to Original. It is normally grayed out, but if you have made any changes to the image it is selectable.
So, as you can see iPhoto already makes a backup of your file. The only problem is that they're both on the same hard drive. It'd be nice if Apple provided options for selecting the folder to place your originals in as well as your images -- that way those of us on LANs or with FireWire drives could easily have iPhoto backup to a separate drive.