In general, how acceptable are these kinds of constructions in English?
Prepositions usually take nominal phrases (I include nouns, nominal clauses, etc. in that term) as objects, but some guides accept that other constituents (PPs, adverbs, etc.) can also serve in that role. It depends to a great extent on how strict (prescriptivist) you'd like to be. For example, Greenbaum allows "prepositional phrase as complement" (of a preposition), providing this example:
That means he took one lamb burger out of there from under the grill.1
Do any situations exist where it might be totally impermissible?
If you're a totalitarian prescriptivist on this issue, then it's totally impermissible in all situations. Otherwise, I don't know of any such situations.
And do any grammatical contexts exist where it is very idiomatic?
Yes! In addition to Greenbaum's example, there are sentences such as:
I've lived here for over twenty years.
I'll save the cake for after dinner.
1 Sydney Greenbaum, The Oxford English Grammar (New York: Oxford University Press, 1996), section 5.47.