We can do this. Much of the code is already there.
Mostly when this has come up before, it was usually a curiosity question, “I see a misheap, why isn’t there a maxheap?”. There wasn’t much in the way of actual needs other than being given this as a homework problem or coding challenge. That said, I’ve had some use cases and would like it if the functionality were exposed.
I’ll work on it soonish.