... we can render any volume bootable by simply installing OS X on it. Well... doing such was a simple task once upon a time, until Lion came along. Since i don't have Lion, i can't speak from experience as to how easy/possible that tactic remains nowadays.
When I got my hands on 10.7.0, I happened to have a number of brand new empty hard drives at hand, and experimented with different installation options. One thing I discovered is that it's very easy to clone the Lion installer (specifically the InstallESD.dmg file embedded in it) onto a Time Machine backup. (Mount InstallESD.dmg as a volume, then use SuperDuper to clone it to the TM volume. SD recognizes the TM backup, and does not erase it during a clone.) This worked extremely well. Booting from that volume gave you all the Lion Installer features, including both the ability to restore from backup, even from the backup on the very same volume, and the ability to install Lion fresh.
Then Apple came out with 10.7.2, which automatically makes TM backups bootable. Unfortunately, it makes them boot into the equivalent of the RecoveryHD partition. You can still restore from backup, but you don't have the full Lion Installer. In particular, installing Lion on a new partition entails re-downloading it from the internet, just as installing from Recovery HD would.
That's still almost
as good as what I had, and has the virtue of being automatic. It just annoys me that in making things easier for most users, Apple downgraded my