I'm not saying that it can't be done but Canon probably figure why go to all the trouble when stills photographers just use the LCD for reviewing images & rarely use Live View for shooting photographs so an articulating screen isn't needed?(Nigel said: "An articulating LCD screen is never going to appear on a rugged weatherproofed professional DSLR. It will get snapped off or the hinge will let in water or similar.")
Never? Professional & prosumer camcorders have featured articulated LCD screens for ages. Don't recall this being a common breakage issue.
And even a relatively inexpensive prosumer camcorder can be dust & rain-proof (e.g.: Sony NX70):
http://www.bhphotovideo.com/c/product/761581-REG/Sony_HXR_NX70U_HXR_NX70_Compact_Dust_and.html