I chatted with Land's End last night, but didn't think to ask for a "fit specialist" (I wish I'd read Rhonna's note first!). I gave her my measurements (I'd taken them all - I'd done enough research by that point to know I needed the Torso measurement), and she straight out told me "we only go up to a DDD". She didn't say anything about them running large (and now I'm wondering if I might try one of their DDD, since H is only one up from G).
Because of all my curves, it makes that torso measurement kind of high, but the actual length of my torso isn't that great (especially the top part). I've ALWAYS had trouble with bras (especially sports bras) and swim suits being too long on the shoulder strap. Which doesn't help with support.
But torsie24 is right - the most important thing (especially if you're going to a water park) is SUPPORT! Goodness knows there's been enough trouble at the waterparks lately - I don't need to be contributing to it with any impromtu anatomy lessons.