Can I run windows 7 for gaming purposes over a external thunderbolt ssd?

Hi apple community :)

I love using my new powerful MacBook Pro, but all work and no play makes me a bored boy... So I was thinking of installing windows 7 using boot camp assistant so I can play games using windows and do everything else comftorbly on OS X. But I don't want to partition 250 gigs of space for windows 7 and it's contents on my internal hard disk. So this theory came to mind, that if I get a thunderbolt SSD, (around 250 gig) I can install windows on it and play all my favorite games my uncle has introduced me to on his beastly PC. Would this work as I think (and hope) it will? I don't know much about this sort of stuff so an in depth (and simplified) explanation would be appreciated!