I'm just 5' 9" ... and shrinking so I'm not much help here. The Dutch though are the tallest folks on the planet and I've seen my share of really tall guys on bikes.

Have you given thought of having your dealer ordering a Dutch brand? I just looked at Koga (is that well known by you guys) and they offer a 60 and 63 cm frame. I would think that would do the trick. I've also seen a 61 cm offered by them.

Here's one link ... Koga // Bikes > City & Touring > Collection