The problem with bootable backups is that you need root access to do the types of low level disk writing required. Thus, you need a very trusted environment.
That said, you can also use CCC and SuperDuper to backup to a disk image file. This would not be directly bootable, but it can be copied to a new hard drive which would then be bootable. Backing up to remote disk images is much slower than the root method to drive method.
