I do not have your fashion forward style, Anna, but, as a size 14, I share much of your shopping difficulty. One of my pet peeves is the fact that, when you move from the 10-12 (and higher), instead of 1" difference between sizes, you have 1.5", and sometimes 2". It can make it hard to find the right fit. I've also found two things recently:
1. Companies seem to be "reversing" the vanity sizing, which was, frankly, working for me.
2. Manufacturers are making the same garment in different fabrics, with no regard for difference in the stretch and weight of the fibers. So, the same jeans in two washes will have sharply divergent fits. Ugh.
Levis, which were my favorite jeans last year, are now prime exhibits of annoying thing #1, and annoying thing #2. And I'm not buying their "designer" line. Mind you, I still have fine fitting older Levis in my closet!
Do you have any boutiques which might have SA's that would be helpful? Or an SA at a better department store?
One last thing: I've been following this blog: http://the12ishstyle.com/category/fashion/
She's actually a friend of Man Repeller. A little too edgy for me sometimes, but certainly not for you, and she does good reviews.