I haven't seen any hard numbers, either...
...but the Shimano SL stuff all seem to have wide platforms, as do the Campy Pro-fit ones. I like a wide platform myself, because it should distribute the pedaling force over a greater area, and (I hope) forestall "hot spots." The jury is still out on that one. But what the others have said about platform width ultimately being a function of pedal, cleat, and shoe rings true.
You might want to just go to a shop, and take a look at them.
...but the Shimano SL stuff all seem to have wide platforms, as do the Campy Pro-fit ones. I like a wide platform myself, because it should distribute the pedaling force over a greater area, and (I hope) forestall "hot spots." The jury is still out on that one. But what the others have said about platform width ultimately being a function of pedal, cleat, and shoe rings true.
You might want to just go to a shop, and take a look at them.