One thing that made me doubt an early 70D was the UK cashback scheme, from the start of this month that runs until the end of May, included the 7D and 70D but not 650D. That said, shortages of the 60D suggested it might be sooner.
I used to be able to look at the timeline of Canon announcements and spot the progression and timing, but once they ditched the 1Ds3 it started getting a lot less predictable (the timeline is about 1/3 down the page I mentioned earlier).
Some things seem more 'obvious' from it (5D4 in 2015?) but I'm always aware of the disclaimer I've long put at the top of most rumour pages;
"We've been keeping tabs on (mostly) Canon rumours for several years and receive all kinds of suggestions - some more believable than others. Please do use your common sense when reading these pages, and remember that they are here for entertainment as much as anything else."
My own 'waiting' is for what may replace or supplement my 2007 1Ds3 for my day to day work - the 1DX just isn't that much of an upgrade, for the work I do (important caveat)