In Japan and China, Canon offers the Canon EOS M2, a slightly upgraded version of the original. However, this camera isn't scheduled for release in the rest of the world.
A recent interview with Masaya Maeda from Canon Japan appears to suggest that a new M body could be on the way in the second half of 2014, with additional lenses.
We might also be treated to a prosumer/professional mirror less camera. With the likes of Sony, Panasonic and Olympus performing well in this field, it wouldn't be a surprise to see Canon showing an interest in this sector of the market too.
Update: The latest rumors suggest that two new mirrorless cameras will be making an appearance at Photokina this year. That would make a good starting place for a "relaunch" of this line.
Although Canon maintains it is committed to the M range, we haven't seen any new cameras since the first one was launched, and unlike pretty much every other manufacturer, Canon doesn't have different models to suit different needs. At Photokina, that could all change with one entry-level model, and another aimed at the prosumer. Additional lenses also seem likely.
Canon high pixel-count camera rumors
Best DSLR: top cameras by price and brand
Nikon has pretty much led the way with high resolution cameras, with the Nikon D800 boasting a whopping 36 million pixels. We've also now got the Sony A7R, which uses a 36 million pixel full-frame chip.
Canon on the other hand has been rather more reserved in its equivalent offering, with the 5D Mark III offering the more modest 22 million pixels.
Still, rumors continue to persist that Canon is preparing its own very high resolution model, most likely to feature over 40 million pixels and probably featuring at the very top of Canon's DSLR lineup.
Although it's been running around the rumor mill for some time, it seems likely that we'll be waiting for a while longer for such a model to appear and we're unsure of such a camera's moniker - some have suggested the Canon 1DSx could be a possible name, though.
Canon 5D Mark IV rumors
There were four years between the announcement of the EOS 5D Mark II and the Canon 5D Mark III, but improvements and upgrades tend to move at quicker pace these days, so it's not totally out of the realms of possibility that 2014 could see an upgrade to the Mark III - just two years later.
Canon now has two full-frame models in the "prosumer" section of its line-up, but it seems likely that the 5D line would be replaced before the 6D, the newer model.