OK, perhaps this is some sort of record. The top Aussie boulderer James Scarborough has completed Hogwart Express (we're looking for the tie-in but we couldn't get the sponsorship... darn), an F8A+.
You want to know what the problem is like? Well, short. Very short. One move, in fact.
Pics of the place (but not apparently the problem which judging by its name is pretty new) at Uncarved Block's site.