Wasn’t Norman French the guy who played Mr. Roper?
Anyway, I’m not sure we’re disagreeing; I accept that the inconsistency goes way back.
Sure. And they can call home runs “dingers” or “jacks,” too, conversationally. “HR” still stands for “home runs” as readily as it does “home run.”
It’s not criminal. But I maintain that it’s nonsensical, and therefore inappropriate in formal writing, to pluralize a numerical abbreviation. Would you write that you were driving at 65 MPHs?
I can think of one postpositional adjective that doesn’t come from that source. Instead, it’s from Gaelic. I’ll spoiler it so everyone can try to guess.
“Galore.” As in, “The Attorneys General had law degrees galore.”
I always order flaming yawn, but they never hear it.
I have enough trouble ordering a panino.
The title Solicitor General (the top appellate lawyer for the U.S. government) follows the same model. An aside: I hate the tradition of referring to AG and the SG on second reference simply as “General” (heard it a bit in the Elena Kagan hearings this summer). It’s a bit of almost faux-military verbiage that just… irritates me.
True. The Master speaks: Why does the U.S. surgeon general wear a uniform? - The Straight Dope
The Chicago Manual of Style (15th Edition) disagrees with you:
No qualification on whether the abbreviation represents a count noun or not.
As in examples given above, you would say “15 POWs,” not “15 POW,” and “100 MREs,” not “100 MRE.”
My inclination would be to write 65 MPH, but because it’s a rate and thus a continuous variable. However, according to Chicago Style 65 MPHs would be correct.
This originates in an adjectival use.
No, it’s an abbreviation of “captain general.”
Has a graffiti artist ever just made one graffito?
Surely one of those is more than enough? 
We also have Lords Lieutenant, though not Sergeants Major for some reason.
Note that in countries with QE2 as their monarch, for the whole country she is represented by the Governor General, while for its political subdivisions she is represented by Lieutenant Governors.
Probably as often as someone eats one spaghetto.
Someone might, however, eat one raviolo 
Or one zucchinus?
The Surgeon General of the United States is not a Vice Admiral; his rank is the equivalent (same pay grade). [url=]Here (PDF) is the official PHS blurb on ranks:
The actual names of the grades are listed, along with the Navy equivalents, on Page 33 of said manual. Of special note is this comment in that table:
Monty, your link doesn’t work.
Not quite. There are only two Commonwealth countries with political subdivisions having viceroys as their heads of state: Australia and Canada. In the States of Australia, HM is represented by Governors; in the Provinces of Canada; HM is represented by Lieutenant Governors (Lieutenants-gouverneurs in French).
It’s Italian, not Latin: it would be “uno zucchino”.
Thanks, acsenray. Here is the correct PDF link.
Furthermore, we USN Sailors are often reffered to as Squids*. That doesn’t mean we really are squids.
*Except for me. You can call me Calamari. I’m a Monterey boy. 
There’s gotta be an exception for that in the Chicago Manual of Style. I can’t imagine that style book advocating MPHs. I’ve never seen such a usage in print, ever.
Anyhow, I agree that RBIs is fine, and MPHs is weird, and it does have something to do with MPH being a rate, although I can’t quite put my finger on how to best explain the difference.