roger, I know it will come across as, at best, questionable. I just want to know if I can be confident in using who/whom.
From what I’ve seen I’m scrapping the ‘m’ and going with “who” exclusively. And if anyone has a problem with it, they can bring it up to me. I’ve mentioned how big I am, and I should be in charge of all rules. 
Duffer, I think etmiller’s on the money here; and ‘twimc’ will only survive because it’s a formual, like “how do you do?”, which after all though it has the form of question (interrogative) doesn’t function as one. (You can’t very well answer “very well, thank you”!)
These kind of fossilised forms stick around in all languages. If it wasn’t for the furious debate that would be caused owing to my unorthodox views on evolution, one might say that such forms are analagous to scattered dinosaurs that somehow survived the cull.
You can’t? That’s the way I’ve always answered – or some variant like “Fine, thank you. And you?” How do you answer it?
On the other hand, I rarely hear “How do you do?” these days.
In Standard British English, ‘how do you do?’ is typically responded to by ‘how do you do? (Nice weather we’re having).’ In other words, it’s one half of an adjacency pair, both halfs of which are the same. Doesn’t Italian operate in a siumilar way with ‘ciao’? (My Italian’s limited to BBC introductory level, with this sultry bird saying ‘allora, ascolta’ rather seductively (or should that be ‘rather rapingly’ in honour of Andrea Dworkin?). I remember especially ‘per andare Roma?’, for some reason.)
Confirmation from The Hindu newspaper that American Englsih and Standard British English differ a bit on this matter (with another nice example of two identical adjacency pairs, this time “namaste” (presumably Hindi)).
But then that great Anglophile snob (just joking) Miss Manners (NB even her title Miss rather than Ms acts to self-identify her as traditional, anti-feminist, etc.)
endorses the British usage:
So, as ever, you pays your money (to Judith Martin’s retirement fund) and takes your choice.
Yeah, but Judith’s an old stick in the mud, isn’t she?