'Oil produced' vs 'produced oil', take 2

Recently a question was asked here on EL&U:

This is the sentence I’m confused about:

After eight years, the amount of oil produced rose significantly.

Why is it oil produced and not produced oil?

Our mods saw it fit to move it to ELL, which I think is a shame. I think it is a very good question for EL&U, because it raises two issues.

First issue: indeed, why is the postpositive form preferred here?

It is not the case that produced oil would be unidiomatic. After all, the following appears in the OED as a sample sentence for the adjective produced:

2001 K. S. Deffeyes Hubbert’s Peak vii. 146        All the produced oil goes to refineries.

Furthermore, we have the following attested examples:

the amount of produced oil that was received by that battery during the month (source)
At the same time the amount of produced oil depends on footage drilled (source)

Acceptability of the attributive form notwithstanding, the postpositive form is clearly more common (or at least it has been, historically), as the google NGram makes clear:

We get similar NGrams for other constructions, such as the oil produced was vs the produced oil was; of oil produced is vs. of produced oil is; and of oil produced was vs. of produced oil was. The idea is to ensure that we are comparing the phrase produced oil to oil produced, but not to e.g. oil produced by…

So, why is the postpositive form preferred (or at least it has been, until very recently)? The only thing I can think of is that produced is relatively ‘heavy’, and the heavier the construction, the more likely it is to be postposed. But that of course doesn’t explain why, then, even ‘heavier’ adjectives like beautiful aren’t postposed. Could it be the homophony with the past participle? (Indeed, one answerer’s preferred analysis is that produced is a reduced relative clause, an ellipsis of which had been produced. More on that later.) Well, such a homophony doesn’t always result in a clear preference for the postpositive function:

Second issue: what is the most likely syntactical analysis of oil produced?

In addition to the question of what makes the postpositive form more likely than the attributive form, there is also the question of how to analyze the construction. Is produced in oil produced best analyzed as a reduced relative clause, or as a postposed adjective?

It is certainly possible for it to be a postposed adjective. First of all, it can be an adjective. This is clear because it can function as a predicative complement (PC), which, in turn, is clear because of the acceptability of sentences like

Its products, from gear oil to gasoline, became produced in tens of thousands of refineries. (source)

(See CGEL, p. 530.)

And certainly some single adjectives can appear in both attributive and postpositive functions: happy people and someone happy. True, single postpositive adjectives modifying a noun (as opposed to modifying compound determinatives like something, anyone, nobody, etc.) are rare. But they are not nonexistent:

the only day suitable, years past, proof positive, matters financial, all things Irish

(This discussion is taken from CGEL, pp. 445 and 538.)

On the other hand, it is also possible that produced is an ellipted relative clause. ComGEL, for example, says this (p. 420):

Adjectives with complementation normally cannot have attributive position but require postposition.

Compare: a suitable actor BUT NOT: a *suitable for the part actor

The complementation can be a prepositional phrase or a to-infinitive clause: I know an actor suitable for the part. …

The postpositive structures can of course be regarded as reduced relative clauses:

I know an actor who is suitable for the part.

However, I think that explanation involving ellipsis should be the last resort, otherwise one could postulate them without end.

Summary

Why is the postpositive form oil produced more frequent than the attributive form produced oil?

How should oil produced be syntactically analyzed?