I eventually got Merriam-Webster’s Concise Dictionary of English Usage, as often recommended by Mark Liberman on Language Log. Well, he recommends the non-concise one. Here’s a recommendation and quote, on the topic of ‘I appreciate you/your coming over to help me’ (that is one of those cases where every time I use the accusative ‘you’ form, I am worried about people thinking it’s wrong).
I should have got the longer one, of course – the concise one doesn’t look very concise, though.
A commenter on that entry points out that the whole book is available on Google Books.