Market analysis aside, I could easily see it. After browsing around at our local camera shop, it seems that the current MF trends are in integrated, automated, system cameras (as opposed to legacy systems with digital backs), and if a small-format company like Leica is getting into the game, I could see Canon doing the same, seeing as they've done similar with the cine cameras. Seeing as Canon has their fingers in everything from P&S to SLRs to video and cinematography, they'd have a user base to tap into.
Or it would cannibalize some of the EOS line. Who knows--not me, I ain't no businessman.
Part of me could imagine a world in the future where the small-format DSLR is mostly extinct, with MF systems taking the high-resolution commercial work end of things, and mirrorless cameras taking the rest. I already use the latter for most of my personal (digital) work, ranging from landscapes while hiking to people photography.