Canon could very well be working on a new design for a Wi-Fi adapter and that would be sitting inside your camera’s SD card slot. Yes. You read it right. Though there has not been an explicit implication that the new Wi-Fi adapter is going to look like a SD card or where it could fit in, but the dimensions are pretty much a giveaway.
The dimensions of the Wi-Fi adapter, named W-E1 is 24mm x 32mm x 2.1mm. It as you can see it matches the specifications of that of a normal SD card. The specifications allow for it to be slotted into the SD card slot and use without anything sticking out.
Here are the full specifications of the Wi-Fi adapter as obtained by digicame-info.com: