I finally picked up an American Eagle denim jacket (something Angie mentioned quite some time ago) this past fall at an AE factory outlet store (my dip into the idea without spending a whole lot at first), and I wear a size 36D bra. I sized up to a size large in the jacket, and it fits quite nicely - but I only really wear it with skirts and dresses, since it's fairly cropped.
The one I got was this one:
http://www.ae.com/web/browse/p.....cat5460159
They also have a darker version:
http://www.ae.com/web/browse/p.....cat6010001
A black washed version:
http://www.ae.com/web/browse/p.....cat4260032
A faded version (oddly, their faded version looks darker than the regular one):
http://www.ae.com/web/browse/p.....cat4260032
I like the one I got - kind of a normal faded, but not "faded in a weird way" wash (first one linked). Like I said, I sized up to a large, and it fits me quite well, despite a 36D bra size. I would recommend trying an American Eagle brand cropped denim jacket and sizing up a wee bit. They're a little bit too short to wear with pants though, so it depends on what you want to wear the denim jacket with. The shoulders fit beautifully and in a size large, the jacket works just fine on someone (me) who wears a 36D bra size. Further- after trying umpteen denim jackets - this was "the one" - it fits beautifully in the shoulders, waist and bust area. In the past, jackets that fit my bust were too big in the shoulders, too baggy around the waist or what have you.
The AE jacket is a winner, imo. Just for reference, I wear clothing in sizes 8-12...my norm is about a 10, sometimes a 12 depending on brand.
editing to add: we won't talk about the fact that I spent about a year trying on various denim jackets, to no avail, and when I finally decided to just go into an AE store and try on the jacket that Angie had mentioned a long, long time ago - it was an "Aha!" moment.
