Have you looked at eShakti, @user23124? They have loads of dresses on there, and you can customise them - so if there is one that is similar to what you want, you can alter the length, neckline and sleeves to make it closer.
You can either order a stock size, or you can give them all your measurements, and the dress is made to fit. It's an American site, but the work is done in India, I think.
I ordered a dress from there for ds1's wedding, and it was perfect - and fitted beautifully. It does take a few weeks for the dress to be made and delivered, but I thought it was worth the wait. And their prices are pretty reasonable too - around the £100 mark, if I recall correctly.
Or you could see if you can find a local dressmaker/seamstress, and show them the image - I'm sure they could make something for you.