Hope you don't mind me butting in... I just saw this thread and wanted to share some info I came across by Louise Porter. I'm a massive Porter fan and she does a lot of work regarding gifted children.

I noticed she had this fact sheet on her website which answers some questions discussed in this thread:
http://www.louiseporter.com.au/pdfs/...edness_web.pdf

I also organised a phone consult with her via skype last week to discuss my own son (autism) and it was great. Just wanted to let you know if you're interested in asking her some questions because it was $75, so cheap compared to some psychs and she has opinions I really value.

ETA: I linked the wrong article... I meant this one:
Twelve myths of gifted education