Weekend at Bernie’s 3, starring de-aged versions of Terry Kiser, Andrew McCarthy, and Jonathan Silverman. The salary of the three stars plus the money spent on the de-aging would be a substantial part of the budget. The plot would be the adventures of Richard and Larry on the yacht to Monte Carlo from the end of part 2, with Bernie (arrow in the head and all) along for the ride. Using a real life mega yacht (to make it more realistic 
) would also eat up a large chunk of the budget.
Buy it brand-new for the film, and then actually sink it in the middle of the ocean for the big finale, so that none of its value can be recovered after filming is done.
I don’t know. Several years ago somebody came up with a musical version of Plan Nine from Outer Space at the University of Utah. I missed it by one year. It subsequently toured the Midwest. I’d pay money to see that. (One of the songs described plans one through Eight).
There’s a musical version of Plan Nine on YouTube, but I don’t know if it has anything to do with this version.
For the trecord, THIS is the version I just missed seeing
With those people involved, I’d watch it! 
My proposal is simply:
Green Lantern 2 
Well, Robert Rodriguez and Tarantino spent $70 million in 2007 to faithfully re-create a pair of $100,000 1970s exploitation films (in 2024 dollars that’s $580k, but that $70M in 2024 dollars is over $100M).
I don’t see how a documentary figures into this scheme.
For my suggestion, any DC Comics superhero flick.
How about a bad Marvel movie?
Millie the Model – The Movie
Naked Gun: The Nordberg Files. But I think I missed my window. Maybe Bill Cosby is available.
ETA: God damn you Seth McFarland!
I don’t know if you’re aware of it, but among the many Edgar Allen Poe adaptations starring Vincent Price, one of them almost fits this description. An Evening of Edgar Allen Poe is simply Price dramatically reading four Poe stories, in costume. The four are *The Tell-Tale Heart, The Sphinx, The Cask of Amontillado, * and The Pit and the Pendulum. It’s certainly the most faithful Poe ever put on film, because it basically IS Poe.
Musdic by Les Baxter, not John Williams.
Roger Corman wasn’t involved in any way
But Drew Carey reading Milton…Uhhhhhh.
Have you ever tried to read Paradise Lost?
50 Shades of Grey as read by Gilbert Gottfried. Most of the money would be spent trying to resurrect Gottfried.
Flatland - The Motion Picture
In 3-D!
It’s been done.
Multiple times, in fact
https://www.imdb.com/title/tt0814106/
https://store.der.org/flatland-p820.aspx
(and the Outer Limits episode Behold…Eck! is also based on Flatland – https://en.wikipedia.org/wiki/Behold,_Eck! )
Making it in 3D is actually a great idea for the scenes where the Square interacts with the Sphere. In fact, for some scenes I’d suggest making it in 4D, if that existed.
This is the first book in a four-book EPIC SAGA. (I read only the first two, and I remember about “this” much. Hey I was young and bored)
It involves time travelers to the Pilocene epoch, aliens, “metaphysic practitioners”, a dry Mediterranean Sea, and none of it is in any way memorable or important. But the budget! It could rival Avatar for cg, unless they wanted to use practical effects.
And since this is only book one of a series, it basically is there just to set up the world of the story. It would be like Dune part 1, except without a built in fanbase.
We could really film all four at the same time! Saves money, or, actually, loses even more before the first one hits the threater and bombs. The other three can go direct to streaming.
I would buy the rights for an American remake of this, but darker and with a more realistic CGI anthropomorphic blood clot.
I think most of your movies, having action sequences, run the risk of finding an audience, if only for hate-watching.
Mine would be a three-hour epic, with expensive actors, of Proust’s À la recherche du temps perdu - in French with English subtitles. It would, of course, involve lovingly recreating the period costumes, interiors, and architecture. Since there are very few internationally acclaimed expensive French actors, the studio would have to pay for extensive language coaching. I would have to have an actual working train from the period, and it would probably be necessary to film a bunch of B-roll of WWI in order to illustrate the Horrors of War. There would be absolutely no explicit scenes of sex or bloodshed, just a whole lot of characters having conversations. In French. With subtitles.
Read it in college. Great story once you can get through the complicated verbiage.
Gilligan’s Island – a Michael Bay film.
A three and a half- hour long biopic of Mao Zedong, focusing entirely on his early life pre-1949 and almost completely ignoring war and politics in favor of his personal relationships with family, friends and colleagues.
I’m not sure this would be greenlit in 2024. And the running time is implausible.
But overall, I think you’re on a much better track than the subsequent answers. If you truly want to get something funded and have it sink like a stone. Take an existing but hoary property that there are a lot of shallow memories of, but a limited dedicated fanbase. That draws in some level of starpower. But the combination of the property being old and out of date, and the remaining tiny fanbase disagreeing with your approach, as surefire a bomb opportunity as you will get.
Also probably helps to get Warren Beatty involved.
Coming in 2026: THE RISE OF HAWKMAN.