Good to see there are others with big hooves out there.
I'm usually a size 13 (bounce between 12-14 depending on brand).
For flats I wear 5-10 Impacts, just checked the size and mine are a US size 14. Good, comfortable shoe, plenty of grip. These are the basic black ones, when I looked they were the only ones that were available in the bigger size (No GM or SH available above size 12), but they may because of the importer.
For SPD's I've got Shimano AM45's, these are the old ones (~4yrs) but have been great as my 'usual' riding shoe. You should be able to find a couple of brands that go big enough.