Originally Posted by notwithit
I tried the 48, and it looked easily a size or two big in every dimension...the shoulders drooped, the body was super-boxy, and the sleeves hung down to KJ-esque levels.
I actually have he 48 (we are about the same size), and I think that it fits perfectly. I am probably 1/2 a size bigger than you, and I have, apparently, a much longer wingspan. The arms hit at about the same place, but the shoulders are more relaxed, and there is more room through the body, and slightly longer. I personally think that the it looks best that way, though you are entitled to interpret it for yourself. Mine looks nearly exactly like in the picture that Mortar had up, which is relaxed, but slim. It's a very lightweight piece (thick, but it's like a knit bonded to polartech, hard to explain), so it doesn't "droop" the way a heavier piece would.
I will wear a shrunken jacket as well, but in that case, I like really saggy, baggy jeans, and some kicks. The idea in that case is to get the silhouette of an aikido uniform. There is an awesome picture of Hidetoshi Nakata in Emporio Armani from a while ago in either an Esquire or GQ shoot that shows a great example of this silhouette. Actually, a lot of Armani, who was always Japanese influenced, uses this silhouette, pairing a fitted jacket with a pinched waist with flowing pants.