It has come to light that there are some...strange...coincidences about this new Supergirl and a fan-fiction story written by a guy called The Laughing Vulcan not too long after MHR.
1. her method of arriving (enough difference to shrug it off)
2. the writing on the rocket (still some difference...
3. powered up upon arriving on Earth in similar manners
4. learning english rather quickly.
5. training with the Amazons
Now I am pretty sure it is all coincidence...but the similarities are enough to make one pause and consider where Jeph Loeb got his idea.
BTW, the story in question is called the Return and can bee seen at
http://www.continuumworlds.org/gwframes.htmlDylan