I know you said Lands End didn't work, but echo-ing PP that they may be a good resource, particularly if you are able to size up. My daughter is 8 and wearing 10plus bottoms + rashguard from lands end to the pool and swim practice everyday. And I was just think we'll probably need to go up a size before the summer is up. And I hear you in this struggle, I'm considering trying out some petite sizes with her and skipping jrs altogether b/c its really hard to find clothes, swimsuits and everything else atm.
FWIW some LE is available now at Kohls online. (Thought not in person at my local store unfortunately)
~ Dawn
Our little monkey (4/2011) & his early holiday present 12/12