I had a MOS burger last year in Hawaii, and now that I think about it I think I could reconstruct one on my own.
MOS is a Japanese chain (second largest in Japan after McDonald's!). The burgers have baked rice patties instead of hamburger, and they're served on buns. Different toppings include terriyaki meats, seaweed, etc. The bun is a little different from our usual hamburger bun in order to complement Asian flavors better. It sounds gross (rice and bread? BLEH!) but is surprisingly good.
Does anyone have a better idea what's in these things or how they make and bake the rice patties? Even a photo or a detailed description of the various layers would be really helpful. My memory is failing me.