I've had a number of double skill drops. The only fun part is calling them "poops" instead of "pops".
I swear I remember hearing a (German?) prospect years ago who double popped rebounding when he was something like 18-18-7 inside skills up to 18-18-9. I think it's possible with a crazy combination of elastic effect + height + trainer level + maybe cross-training, but obviously it's so rare it's not really worth mentioning.