I have a Seagull 6x6 rangefinder that has 645 and 6x6 options (the mask is a pair of little barn-doors that fold away into the film wells when not in use). It's a cheap little camera and pretty simple. The downside is that the lens works a little like a soft-focus lens, but not predictably, which is why I quit shooting with it. 1980s Chinese quality control, whatcha gonna do?
Keith- the woman at artomatic's name was Erin. I forget her last name. She had the wall opposite mine. Thinking of Artomatic, while they haven't yet announced the location or started signup for it, there WILL be an Artomatic 2008.