Claire, in my four decades of public school/church, I can't recall ever seeing one. With the "esto nobis" section requiring the double duet between SA and TB layered, I can't imagine a SAB having the same effect, maybe S alternating with A/TB and the accompaniment, but still.....
Happy hunting.
Sounds like a job for.......LINDA SPEVACEK!

I am puzzled by such a request. The tenor part only goes up to an E - it's really a baritone part (well, just the top half of an amateur baritone's range). Considering that most men are baritones (rather than tenors or basses), it would seem a non-issue to divide your bass section (unless you only have one bass). Alternatively, it's also almost entirely within the compass of altos so that you could divide them, too (the low E at the end of sanguine won't project well by many amateur altos, so you might ask the basses to divide on that note to finesse it...).

In any event, this is one very practical reason this piece is so firmly established in the repertoire: Mozart voiced it in a way that most amateur choirs should be able to do it some measure of justice. (I wonder if Haydn inspired him in this regard; in any event, would that more writers of sacred music kept this practical consideration in mind.)

Something is different now for attaching a .PDF file. Is what I just did - above - something that is usable? It's five pages long. Is that too much for this facility?

It's just that our choir is so small we don't have enough men for both parts. :)

I figured out a way to do it SATB with cello taking one part, though...however, I'm still interested in seeing your setting, WGS. Thank you!

The problem with the Mozart is that it is not a liturgical piece as written - for SATB chorus, strings, and organ continuo. Many arrangements simply transcribe the string parts for organ manuals.

As for an SAB arrangement, I have (somewhere) an SATB score with pencil markings for singing it SAB (when Tenor takes the Alto part, Bass takes the Tenor part, or Alto takes the Tenor part, etc.). If I can lay my hands on a Finale .mus file of the SATB score, I could probably whip up an SAB arrangement that would be more-or-less like what I recall my previous arrangement was. At any rate, I think it would be better than the Walter Ehret arrangement.

I just cobbled together an SAB arrangement for the Mozart "Ave verum corpus" and am enclosing the PDF score and an MP3 soundfile. I didn't clean up the "organ" part (which is really just a straight reduction of the string parts).