I have been thinking about this since your post but have not implemented it yet. I will get to it soon. I have a few ideas about how I will do it so that it is optional for those that want it.
I would also like to display the time of day near the persons name in the directory. For example, looking from the US at another users profile in Australia, I will see what time of day it is there for them.
Your feature request of just having the country filed added will take priority of course. I will work on it next week.