It depends on whether or not you plan to wear these shirts untucked. If you want them untucked, you'll probably have to do a lot of searching since most shirts are too long for that. A custom-made shirt from someone like Mytailor or Jantzen might work best for that. But if you plan to tuck in these shirts, then the British slim-fit RTW brigade would work well (Tyrwhitt, Lewin, Hawes & Curtis at the value end and the more expensive shirtmakers like Hilditch & Key, Harvie & Hudson, Thomas Pink). I find most North American shirts, like the ones you can find at Banana Republic or in department sores, to have flimsy-looking collars and just a general frumpier look than most of the British shirts, which is why I'd recommend importing some shirts instead.