Tricia, I feel your pain! I am also petite and had a very difficult time finding a denim jacket to fit. It has taken me about a year (and many returns), but I finally found one I love.
http://canvas.landsend.com/pp/.....038;sku_0=::AAP&CM_MERCH=IDX_00017__0000002217&origin=index
I am almost 5'3" and an inverted triangle like you, so you might find this one will work for you. I ordered a S and an XS and kept the XS. The extra small is 20 1/2" long from the shoulder seam. I normally wear a 4 or 6 top and the size chart says the XS is a 2-4 so you might want to size down. I am small busted so this one may not turn out to be the one for you, but it may be worth a try. The color is great and it's shaped very nicely at the waist and it has spandex, so the shoulder area can be comfortable. Also, you may want to think about whether it really has to fit comfortably buttoned up. Some of the other busty women have ended up purchasing jackets that might be tight across the chest when closed, but could get the waist definition they need and just wear the jacket open all the time. Maybe Angie will comment on this.
If you go on the site and sign up for email, you will get great deals in the mail. Lots of free shipping opportunities and periodically 20 or 25% off. Also you can return items to Sears so you won't have to pay return shipping.
I'm happy I held out for the right one, but it can be a frustrating process, good luck!