Patrick,
Precisely because it is not that common a feature it would be deemed unfair and stupid, since golfers don't want to have to think anymore.
Therefore, I imagine if an architect did sculpt one into a green complex, it would probably be too easy to remove to bother with putting one there in the first place.
It's interesting, though, that this feature isn't that common, but a beautifully carved swale immediately before a green, which has somewhat of a similar effect in its intention to an approach shot, is very common and quite acceptable.
The third at Royal Melbourne West has a marvellous swale in front of it's green; somehow, I don't think the hole would have quite the acclaim if a similarly wonderfully sculpted mound or two repalce dthem.