grammar - "We are all of us engaged in..." What does 'all of us' mean here?

I read the following sentence in Chicago Sun-Times's review of the movie In Time:

We are all of us engaged in the trade of buying and selling time.

The sentence sounds grammatically weird to me. It seems to me that it should be:

All of us are engaged in the trade of buying and selling time.

Another way for me to make any sense of this sentence is adding a couple of dashes (or maybe commas, I'm not good at punctiation):

We are — all of us — constantly engaged in the trade of buying and selling time.

Or does "all of us" have an adverbial meaning? Or maybe "we are all of us" is a set phrase? Please throw some light on this curious issue :)

Update: If it is a grammatically correct sentence, how is it parsed? I assume "We" is the subject, "are engaged" is the predicate. What is the function of "all of us"?

Answer

I agree that it sounds curiously redundant. The "of us" could be removed from any or all of these sentences, and the remainder would convey essentially the same meaning:

We are, all of us, in the grip of various philosophical assumptions, presuppositions, hypotheses, even theories, about the way the world is, and about what matters in life. (M. Rowlands)

We are all of us bound to work toward this end. (T. Roosevelt)

We are sculptures and recordings and movement and canvas stretched, and we are all of us works of art. (K. Curren)

I suppose the redundancy is intended emphasize or reiterate that whatever follows has some universal or all-inclusive quality - although the scope of that inclusiveness depends on the context:

Although our experiences are different we share a common heritage of oppression: we are, all of us, women. (Z. Dé Ishtar)

I would prefer to offset the "all of us" with commas, but as FumbleFingers pointed out, that seems to be a matter of personal preference.

Out of curiousity, I repeated variations of the "we are all of us" search, using "we will all of us" and "we are both of us," to see if those phrases were also found. Both turned up plenty of results, mixed with and without commas (and one made a rather humorous parenthetical exclusion to the inclusiveness of the verbiage):

We are both of us nice of temper; we are both apt to kindle, and warm of resentment. (H. Godwin)

We are, both of us, perfectly capable of taking all sorts of chances. (J. Katzenbach)

By then it will be too late. We will, all of us, have made our
fortunes by then. (F. Norris)

My own prejudice is that we will all of us (except, let it be quickly
admitted, personal injury lawyers) be better off under no-fault than
under traditional tort liability. (H. Ross)