I have a list here:
http://www.amazon.com/Touch-Up.....8;sr=1-647 (in champagne)
http://www.amazon.com/Sam-Edel.....8;sr=1-753 (egyptian or perhaps gunmetal - these are kind of edgy, but might as well throw these in too, right?)
http://www.amazon.com/Barefoot.....8;sr=1-739 (in grey)
http://www.amazon.com/Barefoot.....8;sr=1-734 (in taupe)
http://www.amazon.com/VANELi-W.....8;sr=1-685 (grey)
http://www.amazon.com/French-S.....8;sr=1-661 (nude)
http://www.amazon.com/Amalfi-R.....8;sr=1-656 (white)
http://www.amazon.com/Lava-Wom.....8;sr=1-629 (gold)
Hope this doesn't confuse - just did a search on Amazon for all size 12 dressy flats and tried to pick out things I thought you *might* like and that might work with your dress. Haven't even started on the flat sandals yet.
ETA: just came back to remove one of my links, changed my mind - they weren't dressy enough anyway - but, the main reason I came to edit my post? I am really liking the idea of pink/blush/nude shoes - love the ones Rae posted and the pale pink ones in Kari's list are also extremely pretty. Somewhere in my list is a pair of nude/blush-looking patent shoes as well. I *really* like the pale pink SW's that Rae posted and the pale pink flats that Kari posted that have the flat bow on the back - very pretty!!