I fully support this idea. In general, being a LaTeX user, I am used to distinguish
textit and respect good semantic formatting. The exact look actually is not so critical.
The problem with quotation marks (suggested by bonomo) is, obviously, double quotations. Besides, even putting nice quotation marks is often a problem, as we see in the internet. Besides, I don't see why, while developing a new system, we should stick to methods, coming from ancient times. Going this way, we would still be using a hypen instead of a dash because people were doing so for dozens of years on their typewriters.
Furthermore, the bonomo's notice about blind people makes me see the importance of such a tag, since it would allow smarter programs to properly understand what's meant and read it out accordingly.
For now we have a mess of different styles, there are at least
code, the backticks, the italic, bold, blockquote. Blockquote is the closest to what we need, but is obviously not enough for all situations. So I'd vote for adding a
quote tag for inline quotations.