I know that a lot of people were sad that we switched from +word to "word" to do an exact match for a word. The good news is that we're rolling out a "literal mode" that will search for exactly the words you typed. It does a verbatim match with your words, so it turns off things like spelling corrections, stemming, synonyms, optionalized terms, and so on. I think we saw multiple proposals for this on Hacker News, so…
Some other people in this thread have suggested ¬ as a substitute (and no, it's not on a typical U.S. keyboard). Others point out that ¬ means negation in a typical context. Do you folks index backticks? If not, what about backtick? I guess that wouldn't be too *NIXy; however, most keyboards seem to have one, and if it's not currently indexed, might be a choice. (It's also "sort of quotish", in nature.)
P.S. Hmm... Backtick could cause unexpected results in the case of someone pasting a single quoted value from Word, or similar. Might not be the common, though, and I never did like Word's "smart quotes", anyway. ;-)