GSD Rescue Very Timid

Question
I rescued a German shepherd from the pound a few months ago.  Lola is a 3 year old full blood female.  Upon entering her "cell" she immediately attached to me and was the sweetest.  I played with her for about an hour checking to see if she was snappy when her tail was pulled or back legs were played with because I have two children.  She thought of it as a good excuse to roll on her back and have her belly rubbed and to lick me.  The pound told me she was owned by a woman, liked kids, other dogs, and to ride in cars. She was well groomed, nails cut, and teeth cleaned when I found her at the pound.  I made sure to bring her home about four hours before the kids got there to acclimate her to her new environment.  I quickly figured out that I had rescued a 100 lb Chihuahua who thinks she can lay on me :) The problem is as soon as my boyfriend arrived she immediately became skittish wanting nothing to do with him.  The same thing happened when my children arrived.  After a few months she now has become use to the boyfriend and is now his lap dog too.  However, I cannot seem to get her to warm up to my children. I have a large comfortable kennel for her to hide in if she is feeling overwhelmed and I never let my children act rambunctious around her.  They don't run at her or crowd her. I have been trying to use treats.  I will have one of them sit in the middle of the floor and hold their hand out in front of them palm up with a treat in it. Lola will take the treat but will immediately run away to hide behind me. I have also sat with them one at a time with her by my side and slowly have them reach to pet her.  She immediately shies and runs off. We do this almost every day.  She will go with me at night to check that they are asleep walking up to their beds and sniffing them but she will not do this if they are still awake. I am a deputy sheriff and often have the local deputies, constables, and officers stopping by.  She is very sweet to any females, even strangers, rubbing on them and running up to them wagging her tail but as soon as any man comes onto my property she hides behind me. Do you have any suggestions on what I can further do to acclimate her to my family and friends? She stays in the house with the family.  The pound tells me that she was an outside dog however, she seems to already be house trained we have only had one accident.  We train about an hour a day in the yard learning basic commands and fetch.  She responds to me very well and seems highly intelligent. My children are 6 and 4 son and daughter.  She has not attempted to fear bite anyone as of yet and has already become protective of the house and me. Any suggestions would be greatly appreciated.

Answer
She really sounds to me like a dog that didn't get the socialization  as a young puppy it needed.  The period between 6-12 weeks is very important.  If she saw very few men and children before 12 weeks, she may never be fully comfortable around them.  I think what you have been doing is the right thing and should help eventually.  

You also need to control your emotions.  If you let it stress you, she will sense it and blame it on the people.  There are human limits to how warmly you can greet men, but make your love for your children obvious to her.  I am sure you know a big toothy grin and looking somebody in the eye works well with people.  It is exactly the wrong thing to do with timid dogs.  They see it as a challenge and a threat.  People need to avoid looking directly at the dog and keep their teeth out of sight.