Considering their current pricing: I estimate 4500-6000$.
Ah, price. So much fun to speculate about. The price will of-course heavily depend on where/how they brand it and what tech they put in it. Assuming it's non-gripped as the story says...The high res 6D2 sort of path
If the 50 MP camera is a stripped down FF body, i.e. functional (but not best in class) AF system with limited number of AF points, 3-4 fps burst, lots of design features and tech wholesale ported over from other bodies, etc. Call it a '6D with a huge sensor' (or a 6D2), and it would be around $2,500-3,000 or so. My guess is: no chance they will do this -- not with their first high MP rig.
Too many pros have screamed for high MP for too long, so to put it in a relatively simple FF body would be a let down I think.The 5D4-ish path
If this 50 MP rig is branded the 5D4 and has that 'level' of feature set, options, robustness, etc. plus 1-2 recently newish things they always sneak in -- perhaps anti-flicker mode, intervalometer, automated focus-stacking, etc., then I think it will be in the $3,500-4000 neighborhood as originally posted on this site. My guess: Whether it's branded 5D4 or not, a camera on this level this seems the logical first entry into the high MP game.The all-battlefield workhorse path -- a 5D4 crossed with a 1D5, minus the grip
There's been some talk of a 50 MP rig with X fps with a built in crop mode that gets you 2-3X fps. Think of it like an 'APS-H' switch that you can turn on/off. As the crop + higher burst screams action and sports, such a rig would need to have a really high-end AF system, weathersealing and build quality. They certainly would get north of $4k for such a rig -- how much would seemingly depend on the burst rate. My guess: There's 'too much new' going on at once here, so I don't see this happening. Also, if Canon ever did this, surely it would be a 1D body, right?The No-shadows-can-hide-from-this-sensor path
If this 50 MP rig has fundamentally better sensor tech and is that great game changing sensor that many have asked for, you brand it as something better/higher than 5D (4D or 2D, take your pick) and you charge fundamentally more for it. This is the rig that would flip competitive business, so this could be a $4-5k non-gripped camera. My guess: I have limited confidence that Canon has this in them given their sensors of late, so I'll call this one doubtful.
I give ranges on all the prices as it very well will depend on if Sony's 46 MP sensor is out there by the time Canon launches.