I was reading in another forum and someone mentioned www.giftsofalifetime.com. I have never used them but others said they were very impressed. They do Disney-themed surprises for any occasion, it sounds like. You might want to check them out. Hope this helps!!
I know there are all sorts of great things you can do and I'm a little surprised we haven't had more posts on this one. Food of course is a very romantic idea- Why not try Victoria & Albert's. What is you budget like? Not to be nosey but it would help with suggestions. If you wanted to get her jewellery you can have it delivered in a glass slipper.
At the Christmas Store in the MK, there is a golden Cinderella carriage ornament. It costs about $35, but it is beautiful. I got one a few years ago and it is my favorite.
How about an Italian charm bracelet that you could add a charm to whenever you come back to Disney? I got one for Mother's Day and have given a couple for gifts. You can purchase the starter bracelet at DisneyDirect before the trip