Xhale, I have the same problem as you, and it is incredibly frustrating. I am 5'11", 185 pounds (muscular build), and the proportions of most clothes simply do not work for me. A shirt that fits me in the shoulders (typically a medium) will often be too long and have sleeves that are too small/short (if we're talking a short sleeve shirt).
I have a difficult time finding even the most basic casual wardrobe essentials--solid t-shirts, for example--that fit me well. My latest attempt to buy some t-shirts was at GAP; mediums fit my shoulders perfectly, but were way too long in the body, hanging about 6 inches below my belt. Now, I know I'm not exactly "tall" at 5'11", but I'm not short, either. It is absurd that a size medium t-shirt is so long on me. I of course wear my t-shirts untucked, and like them to fall an inch or two past the bottom of my belt in the front, slightly longer in the back. But I have tried on countless shirts that don't work for me because they are too long. Sizing down is almost never an option, as that usually results in the chest, shoulders, and sleeves being far too small. I might start shirt-shopping with the mentality of finding shirts that fit well in the shoulders and sleeves, even if the body is too long, with the intent of having a tailor shorten them. Anyone had any luck with having shirt hems shortened?
By the way, Xhale, is the shirt in your first few pics the "vintage oxford"? If so, I've got that same shirt (in medium). While the fit of mine isn't optimal, it isn't terrible, either. I wear it casually with jeans (read: untucked) and would prefer the tail to be shorter. It's too full in the body to tuck-in cleanly, as I imagine yours is, too.
