My Eury is just under 2 lbs at 5 months and the vet today told me to not expect her to get bigger than 3 lbs. Fortunately, except for some recent skin and ear irritation that required her to be shaved, she is very healthy. She also has a open fontanel (sp?) but it seems to be slowly getting smaller. She definitely doesn't realize she's small. LOL We have 3 cats, two who are 10lbs and one who is 16lbs, and she LOVES LOVES LOVES to chase them around the house. Here is a picture of her before she was shaved.
PS... if you wanna see what she looks like shaved check out the thread here:
http://www.yorkietalk.com/forums/showthread.php?t=87965