You could try India or SE Asia. There, most good stores will make a made-to-measure suit. They'll ask you to choose the fabric (you'll pay by the yard / meter / some length measure), and then they'll take your measurements. Before the suit is complete, you'll have the option to go into the store, and try on the near-complete suit, and ask them to make changes.
Be sure to either bring a good-fitting suit or some pics of a suit you like. Keep in mind that styles change from region to region, and unless you want the local style, you'll need to tell them exactly what you're looking for. For instance, it's been my experience that Indian suit makers tend to make much tighter pants than those made in the US.