I've found a dress that I love, but it's at least two sizes too large. My measurements are 30 1/2--25 1/2--33. The dress is 34-28-41. It is a lace A-line, strapless, has a lace up corset in the back and extra ruffles/lace on the sides and the train. Can a good tailor take in that much without changing the shape? I'm hesitant because of the ruffles/lace on the side and train, as well as the large difference in hip measurement. I'm also 5'4, so it will need considerable hemming.
Well, that is a question that only a tailor could answer. However, have you already bought the dress? If not, call around to other boutiques and see if they carry it in a smaller size or if they can order it in your size. Buying a dress that fits is the best option. If you do already have the dress, consult with your local tailors and ask for there input.
If you haven't bought it I would find out what salon in your area carries that designer go in, get measured and order it in your size. If that is not an option bring a picture of it with you to other places and try on similar dresses. Good Luck!