iMac 27 2013 and BootCamp (external drive)?

Greetings.
Waiting for my iMac 27 2013 and planning to use Windows 7 on BootCamp. But found out that u basically can't setup Win7 on BootCamp to external drive.
My iMac is ME089 and have 1TB HDD, which I won't really bother to change to SSD, but I got 160gb ssd from previous PC which I would like to use for BootCamp.
So, is it possible to somehow install Win7 and external ssd with bootcamp to have dual boot?

I've found this article, but haven't got a change to test it:
http://bleeptobleep.blogspot.fr/2013/02/mac-install-windows-7-or-8-on-external.html
Anyone tried?

Have 2 thoughts.

1. Find out that you can migrate windows from BootCamp to external drive via WinClone 4.3.
Is it a good idea?

2. I got win7 64 installed on my 160 gig ssd now, it's like 1 year old now, super active OS files. Maybe it's possible to run "sysprep" tool, shutdown pc, get out ssd, put it in usb 3.0 enclosure, hook up to iMac and just run it from boot selection? Sysprep will install new drives, and bootcamp drivers will do the rest.
Can the trick do it's job?

So I've played with external drive. Got usb 3.0 enclosure and found hdd from mbp 2008.
Set up Windows with imagex tool and tested out.

Windows 7: Failed to boot, BSOD because of lack of usb 3.0 drivers support to install Windows.
Windows 8.1: Runs fine, system had to make 5 min prep till it fully loads. Installed BootCamp drivers and ready to work.

Huge pros of this installation method - you don't need to put anything on ur Mac hdd. And you won't see Windows in boot camp settings. In other words - Windows works separately from anything on your OS X.

Btw. Old macbook hdd runs at 60mb/s.

Small update.

The idea of puting Windows 8.1 on external hdd via usb 3.0 in overall is not really great idea. Lag spike - and your windows will freeze. So I had to bare with idea that Win 8.1 will live in a bootcamp on a internal hdd.