I think that, given the range of off-the-shelf minivelo offerings I've seen, I'd say that you're probably on the edge of workability, but as fietsbob said, you could go the custom route.
That said, if you want to tackle a production mini, you should probably take a look at this thread,
http://www.bikeforums.net/folding-bi...de-thread.html, paying special attention to the posts from Poguemahone, who is 6'1". I'm 6' myself, and both he and I ride the size L, or 55cm, Mercier Nano.
The thread details some of the mods we've had to make to get comfy on the bikes, and will help you understand some of the challenges and options available in terms of components, and ultimately, fit options.
The Mercier Nano is available from Bikesdirect.com for about $300. If custom is an option, Seven has made some sweet ti framed minis.