I haven't exactly had any possibilities to jump anything massive. There's this 8-10 foot tree that hangs out over some water in downtown Stockholm which is wicked fun:
The bridge behind is also doable, but they've put in all of this sketchy stuff to keep you from climbing it... If you slip, and you're literally climbing on bolts sticking half an inch out from the cement, then you'd slice your entire leg open, then have some serious current to swim with a mangled leg... You can jump up to 80 feet from that, i've only done the 30 though.
The rocks in the Archipelago don't drop off into the water much, it's more of a slope, but i've been one place where you had sweet cliffs, up to 30 feet, most at 15.
Next friday im going to this pool with a 30 footer to do some gainers for the first time off that height, should be fun.
I also just love me a good springboard.