I know what you mean, Ive had a few litters like that, Im working on selectively breeding a few of those right now too.
http://ball-pythons.net/forums/showthread.php?t=32649
This guy was 42 grams before opening eyes, at ~ 14-16 days
He was in a little of 8 I think, and all of them were of that size.
At 4 weeks when I weaned them from the mother they were 120 grams I believe. 140-160 grams at 5 weeks. I will have to check my notes when im back home