Canon has just filed for a patent for a 100% coverage optical viewfinder, which wouldn't be that exciting except that this one is tiny. Instead of the traditional physical adjustment, this patent focuses on an electronically switched transmission / non-transmission of the liquid crystal. This seems to give merit to the rumors last week regarding an updated EOS M with a viewfinder, as that would likely be the only camera small enough to take advantage of this patent.
There is a little bit of well-informed opinion written on the matter at egami.blog, but even with Google translate it's hard to take the broken translations out of Google and rephrase him eloquently. It's best for you to go and read it yourself and glean from it what you can.