Try applying for a position at a large company with a reputation for a highly-engineered hiring process, eg. Google [0]. Rarely will you get specific feedback, but you can expect to get a notification when you are no longer under consideration.

[0] At Google's scale, some candidates fall through the cracks. But their recruiting process does mandate rejection notifications. It'd be great if a Google recruiter would back me up here :)

My impression is that rejection letters are fairly common but they're almost universally in the form letter "no fit at this time. Will keep on file" vein.

Maybe some companies do more personalized responses but I've never seen it and I would think it would often be difficult. As with many other things, say picking talks for conferences, you're usually not so much rejecting as you're picking some other person or thing. And, yes, there are a lot of reasons the typical HR department would have issues with brutal honesty even aside from the effort it would take.

> How long do you think it takes to write a rejection letter that provides useful, actionable data for the potential candidate?

I see nothing in the post nor this thread that indicates that's what people are looking for. An obvious form letter would be just fine. The point is that a candidate wants to know that the process is over, instead of being left hanging.

Facebook gives candidate feedback.

"I am strongly in the "don't hate the player, hate the game" camp on this issue."

I am strongly in the "that is a shitty excuse perpetuated by people to excuse their crappy behavior on a wide number of things" camp.