Saying that ds (not allergic) did have cows milk after 12 mths, but I gave him semi skimmed after he turned 2 because I was worried about the oestrogen levels in full fat. Skimmed is evidently the best, if children are getting adequate fat content in their diet from other sources.
As for alternatives, sardines, pilchards etc are a good source, broccolli and other things mentioned by others, but the problem is that milk packs in the calcium at a much higher ratio than other foods (and I think getting a toddler to eat sardines and pilchards with their bones could prove tricky) DS hates all green veg at the moment, which is a nightmare for me, but if your ds likes these things you can always substitute dairy for these sorts of foods.