http://high-performance-running.com/
BAR shoes. They are kind of built like Birkenstocks. Wide in the toe area. Neutral heel height (most shoes today have the heel higher than the toes). What I would do is buy a size or so larger and wear extra socks till my feet swelled, then start removing sock layers.
These shoes have been featured two years in a row at
badwater and the runners are really starting to warm to them. Fewer blisters, less fatigue.
Or you can do like the old school folks and just cut the top of the toe box off when your feet get too big!
Mike