I know of many offspring, few who look that alike unless they come out as the bigger, lots of white variety. They range in size from 15.2 to 17hh, so yes, I have seen VERY large offspring.
There was a bunch of people I know that seemed to be buying them a while ago. For whatever reason many of them have had major hind end lameness issues. But then again some of them have gone on to do very well in the ring. They were all bought from the same farm, and the breeder took one of the mares back that was never sound as a broodmare.
fwiw all the lame ones had pretty bad hind end conformation, so maybe that needs to be a consideration with the mare.