Well, 'giants' isn't really an improper translation, exactly. As far as I can tell, 'Nephilim' is the original word, which means something akin to 'fallen ones'. However, as many of the sources that refer to Nephilim also refer to them as giants, the word 'giants' was used to replace the more unusual 'Nephilim'.
As far as sources, I mean Genesis, Numbers, Macabees, Amos and certainly all throughout Enoch.
Here's one from Enoch:
"And they became pregnant, and they bare great giants, whose height was three thousand ells[60]: Who consumed all the acquisitions of men. And when men could no longer sustain them, the giants turned against them and devoured mankind. And they began to sin against birds, and beasts, and reptiles, and fish, and to devour one another's flesh, and drink the blood."
Surprisingly (to me at least... I don't usually use answers.com), Answers.com has some pretty good write-ups with references.
http://www.answers.com/topic/nephilim#Nephilim_in_the_Hebrew_Biblehttp://www.answers.com/topic/book-of-enoch#The_Book_of_the_Watchers**********
Anyway, I do think Hulking Size should be a requirement, along with some level of strength bonus, as described in my previous post.
Citadel, you mention the Changeling template... I think that would be great for a 'Descendant of Nephilim'. You just pick from the Nephilim list that we come up with.
As far as the size and mothers, think about the tallest man, Robert Wadlow (
http://en.wikipedia.org/wiki/Robert_Wadlow). He was born at 8lb 6oz (according to Wikipedia, not, of course, a perfect source) and died at 8ft 11in and 490lbs at the age of 22.
Andre, though shorter, was probably closer to a true 'giant' in that his bone structure was heavier, helping his body stand up under the size and weight. But anyway, it looks like around 7-10 feet, at least, is not unreasonable from a normal-sized woman.