Learn English – “The process was done correctly” Confirm the correct steps have been taken

Have you ever been shot at? is acceptable usage. As others have commented, the traditional rule of not ending a sentence with a preposition is not absolute. When I wrote essays in college, we were asked to note parenthetically in the text that our deviations from standard usage were stylistic and intentional.

Google search results for 'I had been done that'

An Internet-wide Google search finds four instances of "I had been done that" that aren't references to this EL&U question. One is from Vicky Laurentina, "I Quit" (February 7, 2015), on her A La Laurentina blog:

I used to be addicted on sugar.

I had habit having a cup of milk each morning. I served myself a mealspoon of milk powder in a cup of water, added with a mealspoon of sugar. I had been done that ever since when my mom taught me to serve my own milk. When I was grown up, I could not enjoy my milk without sugar.

Laurentina seems to live in Indonesia—but I didn't find a post saying whether she is originally from there or from somewhere else. Her English is idiomatically unusual, so I'm not sure what to make of her having used the precise phrase that the OP asks about.

From a response by Aris Batam to "Can I get a KITAS without going out of Indonesia?" (January 14, 2015) on the Living in Indonesia Forum:

For the 1st KITAS need to collect the VISA from Indonesian Embassy. I had been done that 3 times in past 15+ years working in Indonesia. If can, my ex-company will have let agent to do that too.

So that's two of the four posts with a strong connection to Indonesia.

From "Things That You "Shouldn't" Speak Out Loud" (January 24, 2016), on the author's thislittlebirddecidedtofly blog:

Those years when I was supposed to grow as a woman and me, were the worst because I was broken to pieces and didn’t even realize that I had been done that. I thought that it was something that I did, or at least was made to feel like that. When I was already feeling super insecure with myself, and didn’t believe that I deserve only the best, like anyone else.

This author appears to be Danish. She doesn't generally use African American Vernacular English.

And finally in a comment dated November 30, 2013) by Pyuuni regarding a drawing (by Pyuuni) titled "Ouh Souda" on Deviant Art:

kldksjhkafjukl tis true, tis true, we all forget a lil somethin somethin- BUT I COULDVE SWORN I HAD BEEN DONE THAT GOSH. my mem sucks just arghh

and yeeeey there's so much rabu right there hgnhhh i rabu u just like i rabu my..food and cats and that's some serious love man eheeheh u b u

That's not much of a database to go on.

Google search results for 'I been done that'

Things change considerably when you run a Google search not for "I had been done that," but for "I been done that." In the first place, Google finds upwards of 30 matches for "I been done that"—and the matches show up not in the midst of lengthy complex sentences, but as a standalone expression. One intriguing match comes from Evan Jacobson, "Adverbs: Are They "Gradually" Becoming Extinct?" (April 18, 2010):

Inner City children have a unique language. “Brick” actually means “cold.” “Brolic” is a term suggesting how muscular (Buff) a person is. Their subject verb agreement usage would make you cringe: “I been done that cause we was finished like yesterday…” Make no mistake, I have become very fond of my 7th Grade Angels. I have a love and hate relationship with them, but I never actually get to the point of hating them. Even the terrorists have carved a likeable niche in my dendrites.

Jacobson says that he teaches English in a New York City public school at the secondary level.

And from Zachary Hoskins, "Education, civic empowerment, and race: Commentary on Meira Levinson’s No Citizen Left Behind" (2015) (a PDF file):

Why, then, should we think it fair to ask non-White, low-income students to master the skill of codeswitching? It might be fair to ask this if the dominant group’s patterns of speech, dress, or behavior were somehow inherently superior. But as Levinson contends, this is not the case. In discussing the “cultural and hence civic and political bias toward White middle-class norms” (75), she writes: “There is no inherent superiority in wearing pants that have narrow, straight legs rather than legs that bag and bunch. ... No more information is conveyed by explaining ‘I did that already’ in Standard American English than by explaining ‘I been done that’ in Black English, assuming the listener understands both” (ibid.). I would add that the unfairness of privileging White patterns of dress or cultural referents seems especially unfair given the often egregious history of how White culture became dominant in the United States.

And from bosni_fox, "I'm a 21 year old white girl with black parents. AMA" (April 28, 2014) in a Reddit thread:

[deleted] Would you understand the difference in meaning between "He done been work" and "He been done work", for example?

bosni_fox Yep, the first one means he just got off work and the second means he's been out of work for a length of time. But it's weird, seeing it written it took me a second because I only hear it.

...

cbryantl120 You've never heard anyone say "I been done that?" Meaning, I completed that a while ago. This is very common but maybe it's just weird seeing it written out.

And then there are the posts that don't talk about what the phrase means, but just use it. For example, from "Homeless Children Living On The Highway To Disney World" (April 19, 2012) in the Huffington Post:

He [Bobby] didn’t care. He figured there’d be plenty of time for studying when he got to college. “All my friends will be like, ‘Bobby, let’s party,’ and I’ll be like, ‘Nah, I been done that. Now I’m all about the books.’ For now, the plan was to have as much fun as possible. He knew his carefree days were numbered. Earlier that week, he found out he’s going to be a father.

From "Vogue approves big butts; black people already did: Jarvis DeBerry" in the New Orleans [Louisiana] Times-Picayune (September 12, 2014) [page no longer appears when linked to]:

Metaphorically speaking, Vogue's article is praising the skill of Paul Mares. And Louis Armstrong is reading it and thinking, "I been done that!"

And from comments associated with music charts posted by Tree Cecil B on SoundCloud (2014):

Yo lil bro i been done that song ima send you that jawn tomar afternoon. Btw this track hot. Ya best jawn. Keep up the good work

Conclusions

It appears that some strains of Black English have a standard phrase rendered as "I been done that," whose meaning is equivalent to "I already did that." There does not, however, appear to be a widely used Black English expression of the form "I had been done that."

It occurs to me that the phrase may have passed through an intermediate phase along the lines of "I have been and done that," analogously to "I went and did that" (or perhaps, more closely, to "I have gone and done that"). But I have no evidence that any such thing happened. Clarence Major, Juba to Jive: A Dictionary of African-American Slang (1994) offers a very different etymological account in this relevant entry for "[been] done":

[Been] Done v. (1920s–1990s) past complete marker; doon (Wolof). The African origin of "done" converging with the English "done" may help to explain the black American particular use of the word. (H[olloway] & V[ass], [The] A[frican] H[eritage of] A[merican] E[nglish] (1993), p. 140.) Example: "I don't know what you talking about, I been done finished the dishes." S[outhern and] N[orthern] U[se]

The idea that Black English use of done in an expression like "I been done that" is a survival of a Wolof (West African) word used to signify completion is certainly intriguing; I'm not qualified to pass judgment on its linguistic merits.