Capitalization – Why Capitalize ‘T’ in ‘T-shirt’?

I invariably struggle towards the simplest possible effective, clear, unambiguous answer. Often, these goals can't be fully met, but I try.

In my opinion, the best version of your sentence is this:

The question is, "Should 'should' in this sentence be capitalized?".

1. The virtue of this version is that it is absolutely unambiguous. Clarity in communication is usually my number one goal.

2. The sentence is declarative. An interrogative sentence is embedded within this declarative sentence as nothing more than the object of the sentence. It does not change the nature or kind of the sentence any more than dog changes he petted his dog into any other kind of sentence. It is possible to omit the concluding period as being unnecessary punctuation, and I wouldn't quibble over that, but even if you took it out, it would not change the sentence into an interrogative. The mere fact of the concluding punctuation (in that case) being a question mark would not define what type of sentence it is, because it applies only to the embedded question.

I accept, however, that it's possible to reduce the complexity of your sentence down to this:

The question is, should the "should" in this sentence be capitalized.

1. In this case, the embedded question is reasonably well understood from "should" beginning the object phrase, and the question mark is not needed. The period should be used by itself then. I think this version has the virtue of simplicity, although some degree of ambiguity starts to sneak in, so I would be wary of that.

2. I would not agree with a version that removes the comma because then you would create syntactical confusion. The reader would read the sentence as "The question is should," and would be confused about where to go from there; "is should" would seem to be an impossible verb phrase, and suddenly the reader would be lost.

As for your choice of whether to capitalize the word when you are in fact asking whether to capitalize it or not, do it either way, and see what answers you get. Or be creatively clever, thus:

The question is, Should I be considered correct in capitalizing "should" to start this sentence?

Don't think of Australian dollar as a single proper noun. Instead, think of it as a combination of two words, meaning "a dollar that happens to be Australian":

Australian_{proper adjective}　+　dollar_{common noun}

There are lots of kinds of dollars, and we use adjectives like Australian and Canadian to say which sort we're talking about more specifically. There are lots of kinds of rupees, too, and we use adjectives like Indian or Indonesian to specify which sort we mean. Something similar is true of the Japanese yen and Chinese yuan (which are, by the way, etymologically the same word).

Note that in the preceding paragraph I talked about kinds of dollars and kinds of rupees. I didn't just say dollars and rupees, because an individual dollar is a piece of currency! If I have five dollars, I have either five one-dollar bills or I have some other denominations that happen to add up to five dollars. There is no singular dollar—there are many dollars!

Even if the US dollar were the only dollar in existence, the word dollar still wouldn't uniquely identify a single entity. And the same is true of the word cedi. If I have two cedis, I have two hundred pesewas. There is no singular, unique cedi to which the word refers. So semantically speaking, we have no motivation to treat the word as a proper noun. And syntactically, we don't: I can say a cedi or three cedis, just as I can say a dollar or three Australian dollars.

Ultimately, even if it made sense to treat cedi as a proper noun, the fact is, we don't use it like one, so it isn't one. Any additional explanation is just icing on the cake.