What does ending a statement with 「っ」signify when coupled with 「・・・」?

Question

I have seen a few sentences or exclamations that end a sentence with 「っ」. Specifically, I read the example below:

ちなみに純文学について語れなんて言われても私には、無理・・・っ！

The following sentence is listed below (However I'm not sure it is a "new sentence"):

ですので基本的に私が紹介する小説作法は大衆小説についてのものであり、特に得意分野であるライトノベルに通用する話が多いと思います。

Is the 「っ」necessary at the end of this sentence? Does it have any meaning? The only instance where I am familiar with the use of 「っ」is to indicate a pause when pronouncing something. However, since 「・・・」signifies a pause (I think), and an exclamation follows after the 「っ」, what does this actually mean? Does 「・・・っ」　indicate that the last vowel is carried on for sometime, and then abruptly stops?

Would it be any different if the sentence looked like the following?

ちなみに純文学について語れなんて言われても私には、無理・・・!

Answer 1

http://en.wikipedia.org/wiki/Sokuon

The sokuon is also used at the end of a sentence, to indicate a glottal stop (a sharp or cut-off articulation), which may indicate angry or surprised speech.

The equivalent Japanese article also suggests it may be used when a person can't speak, as from a blocked throat or extreme pain.

Often, in manga, it is used effectively as an alternative to an exclamation point (e.g., わかってるよッ　そんなのッ), or in addition to one as well.

Aside from these uses at the end of a sentence, the sokuon may also be used for stuttering (e.g., たっ大したもんだ).

In your example, I think the sokuon plus "!" is slightly different than if it was just "!", but I'm not sure what that intended distinction is (if any)...