Personally, I've always felt that it is the phrase "number of" that is implicit there and that, this being the case, the mentioned phrase needs to be omitted to avoid redundancy -- what else can "50,000" be but a number?
We view it similarly. When I spoke of the "full construction," I used the phrase "something like this," because I don't think that it's a case of recoverable syntactic ellipsis. It's the idea that is understood, and the idea can be clothed in a number of different words: "total of," "number of," "quantity of." Your selection does have the benefit, as you point out, of creating redundancy and thereby motivating deletion. Mine can actually be uttered: "an estimated (total of) 50,000 people."
Surfing the Internet, I have found in this grammar log that "an estimated" may be considered to be acting as an adverb, similar to "approximately," which does make sense, doesn't it?
That's an interesting take. I do note the hesitancy. The author is speculating, just as we are. That "claim" is actually a question, and it is followed by the honest, humble confession "I really don't know."
I think the other, related constructions you've brought up, Gustavo, are excellent. We are clearly dealing with a broad pattern with number phrases, not an isolated oddity that only shows up with the adjective or participle "estimated."
Before reading your post, I had just been considering that very point, though I hadn't come up with so big a list. The adjectives or participles that I was considering were "whopping" and "staggering":
- A staggering 10,000 people were at the beach.
The adjectives and adjectival participles that work in this construction tend, it seems to me, to be ones that pertain to emotional reaction or merely, as with "estimated," to human subjectivity.
I may try to see if there is any information about this in one of the extra-comprehensive grammar tomes in my library. I sense a close family resemblance here to what we see in sentences like "I spent a wonderful four years there."
Perhaps a more distant family resemblance (at the cousin level, not the sibling level) may be said to exist with what we sometimes find with noncount nouns. Here are a few Stephen Crane quotes from The Red Badge of Courage:
- "By the time the depleted regiment had again reached the first open space they were receiving a fast and merciless fire." (i.e. gun-fire)
- "The youth in this contemplation was smitten with a large astonishment."
- "Still, they saw no hesitation in each other's faces, and they nodded a mute and unprotesting assent when a shaggy man near them said in a meek voice: 'We'll git swallowed.'"