I read through the thread last night and I can't remember if this has been suggested, but I thought I'd throw it out there anyway.
Michelle Renee Giusti
http://www.charleyproject.org/cases/g/giusti_michelle.html
Went missing at almost 2 years old from WA with her mother and her sister. What struck me is what her mother looked like:
http://www.charleyproject.org/cases/g/giusti_sharon.html
Am I the only one who see a resemblance between Sharon and LEK? It's not striking, but it's there.
I also ran Michelle's height at 24 months old through a percentile chart and she's taller than 95th percentile (I might have made an error though, I don't know) at her age. She could've grown up to be 5'10''.
I think that using BST's name and identity is a clue somehow. I feel like LEK had ties to WA somehow. Maybe her mother took the kids and left, and LEK later found out about it?
She was also born in 1961, which would work with the theory of LEK being older than she claimed to be. Although giving birth at 47 is less probable, but not entirely impossible.