Take a good look at the feet of many of the top downhill racers (especially the Aussies) and you'll probably see some 'interesting' looking black shoes or boots. They will be FiveTens.
FiveTen makes climbing shoes, but realised its extremely sticky Stealth rubber grips flat pedals like glue. The style of the suede upper lace up shoe and boot version is a little clumpy looking, but you'll forgive that when you try them. Honestly, this is like clipping in. No, really. You have to make a genuine effort to pull your foot up, off the pedal to move your foot on it. If you've always wanted to do the flat pedal thing, but didn't want to give up the clipped-in efficiency, try these out for size.