RedHat Image/Flash/Flar support in RHEL 4 5 6 and 7

Way back in RHEL 4 around 2005 it was painfully slow to do installations.
I then developed a kickstart python class overriding and extending the 
python based anaconda install classes. That way I could stream an
file based image over the tiny initial RHEL installation then bypass
the rest of the kickstart only doing the kernel install and config of
ip interfaces and similar tasks. 

That way I could take a snapshot of a physical box, virtulize, or I 
could take virtual machine and move it to physical box. This cut 
building time from 30 minutes to less than 10 back in 2005. The two files
s-RHAS4.cfg  ks-RHAS4-public.README tells you how it did work.

RedHat removed the ability to override and extend anacondas install
classes in RHEL5. However contrary to RHEL4 you don't need to install 
that many packages in RHEL5 so you can still do imaged based installation
quickly with a bit of normal kickstart scripting. Just install the base rpms
and then add the scripts you see in the ks-RHEL567.cfg examples. You need to 
do your own adjustments for your site but this is giving you an idea how
to go about in RHEL 5,6 or 7 and its peers such as Fedora and Centos

Even if virtualization has made image based installs somewhat less needed
I still can't get around to why RedHat/Debian etc doesn't make it a part 
of their installer. I know there is systemimager but that is not the same.