How many times have you tried to install GNU/Linux from a CD?
Personally, I've lost count after 50+.
I've tried Debian Etch, Ubuntu Dapper, Kubuntu Dapper, Sidux, Arch, FreeBSD, Debian Lenny, Puppy, DSL, and gOS.
It's fun I know, but for the most part, it is a little bit time-consuming and it wastes a lot of CDs.
I've seen it done before - on a WindowsXP machine. A computer technician who used to work for my father installed a copy of WindowsXP on another partition and every time the machine boots, it shows these two options: (a) Install Windows XP (b) Boot to Windows XP Professional.
If it can be done on a Windows machine, it could also be done on a Linux machine.
I've searched Google and asked many times in IRC, but so far no takers.
I am fortunate to have discovered Rakesh Kumar's blog last year and I am happy that he took the time to actually help me on my quest.
Go to http://debaira.blogspot.com/2009/03/boot-iso-image-from-hard-disk.html
for the instructions.
I will update this as I progress.