shadghostGah! Funny you mention the .3mm. I'm a big .3mm fan myself and I've been trying to make that version available. Rotring only ships certain models to America, BUT that can all change depending on the size of the group.
The Rotring 600 was a huge success and it's never been said explicitly but if we can keep placing orders like that, Rotring will have a pretty big incentive to listen to special group requests.