Installing Windows onto a USB HDD

Hello /tech/,
I come with a legitimate question for you

Is there ANY possible way for me to install Windows 7 onto my Western Digital 250gbgb Passport Essential?

I do not own my own computer at the moment, so I have to constantly swap around with my passport to a new computer, and I am getting irritated with it. I received the Passport as a gift, so I don't really care about formatting it (Infact, already did so).

tl;dr

I have a Western Digital 250gb Capacity Passport Essential portable Hard Drive. I want to be able to use this to install windows ONTO it. I have tried google, but all I get is how to boot from Usb or external HDDs, which I already know how to do.

I googled "install xp usb"; I got a page, which was unavailable, but there's a forum discussing this:

http://forums.ngine.de/viewforum.php?f=4

I know this isn't what you asked for, but I installed Knoppix 6.3 (from a Linux magazine DVD) onto a 16-gig SanDisk Cruzer, and it's AWESOME--I'm using right now as I write this. If all you're doing is regular web-surfing and other basic stuff, it's a great way to go.

6.3 isn't officially available off the net yet, but 6.2.1 is, so you might try giving it a shot.  And watch for 6.3 coming out soon....

Why not put the hd into a computer, install normally, then put it back and boot from USB.

Should work perfectly fine except taking epically long amounts of time to load. (USB is typically like 20 megabytes/second)