sigh I feel you're pain. I walk into a sports store and always realize that they do not carry my size. And when I ask for help, they look at me like I'm insane. In highschool, one sales associate told me that she only carried "normal sized bras". That was when I started searching.
I offer two great resources (and links!):
is a little outdated, but will always be my favorite for her sense of humor and for being my first find of empathy. She has some old links, but some good. It's hit-or-miss.
Bigger Brashas the best grid anywhere.
http://www.biggerbras.com/guides-to-lingerie-bras-and-gift-ideas-for-her.shtml is the home to a great chart. Also, there's another chart somewhere on this with website that has sizing for almost any brand (US & European!), even for those with 32K or 48B--it's a big specktrum and a lifesaver if you get nervous about where to order from, what to look for etc.
A lot of gals keep telling me I
need the Enell sports bra, but I'm still too narrow chested w/big bust. But runners do swear by these.
http://www.enell.com/order.html
If you're willing to shell out for shipping,
http://www.bravissimo.com/ has great customer service and a
pretty selection.
Otherwise, I'm a fan of
www.herroom.com and
www.figleaves.com.
And my all-time favorite for when my busom isn't too busting out (reviews, customer service, blatant honesty!) is still
Title 9 Sports. I like Moving Comfort bras (Maia is fabulous even in 100 degree heat!) and Lunaire (encapsulated! No Uni-boob!). I'm getting ready to buy a new one myself and am thinking about either a Shock Absorber or Panache.
Good luck and keep us up to date on the search, where to find good stuff, and comfort!
Cecilia