Mac App Store and Bootable Images

Anyone worth their Mac loving salt knows how hardware agnostic the OS is. Need to send your main computer in for repair because of a faulty batch of harddrives but, want to avoid being out a machine for a couple of important days?

A bootable image is a "snapshot" of everything that is going on at the block level of your OS. In most cases, these images are captured using a firewire drive (hopefully soon to be Thunderbold drive) and can be used to run any other piece of Apple hardware(computers, not iPads). Well sort of.

PPC architecture images can ONLY be booted with PPC Macs and the same goes for Intel. In addition, a Lion image won't even boot on an old coreDuo machine (anyone seen a workaround?). Downtime is reduced to nothing with this method...or usually. For some reason, several of the apps that were purchased from the App Store, annoy the user on startup for a username and password. However when entered, the app simply dissapears. Wonder if anyone else is seeing odd behavior like this?