this is the very very simple explanation...Unfortunately it is also the very wrong explanation. Without getting into what people do for a living or what terms people think are being used, "4K resolution" is the standard everywhere I've looked for video that's 4,000 pixels wide, which would make it akin to 1080p in fact. You are probably thinking about something like bitrate. There's talk of some cameras having the 4K resolution, or of theaters being ready for digital cinema or for 4K resolution (I fancied myself able to tell the difference between previews being shown in low-res while the main feature was at a higher resolution - but I couldn't say for certain if that was 2K and 4K, or 2K and film which is most likely. Stuff I've read suggests that at least within the last few years 4K movie projectors have made some headway, but aren't found everywhere.
Back to the news topic - I'd be wary of private developers overpromising or even just pulling the collective legs of camera users, but I don't see why it's not possible. I wouldn't make any purchasing decisions based on this, but it does stand to reason that they wouldn't have announced to the world that they were working on something before it was ready (which is a point against the idea that this is not legitimate). So I would say - if you own a 550D, something pretty nice is probably coming your way.
No idea how Canon will react to the number of suddenly melted 550D insides appearing at their shops, though - but it probably won't be used so much as to become an epidemic anyway. I do think that the usual advice of using a battery grip probably won't be all that's necessary to help keep it cool, though. And how would firmware reflashing work? For that matter it'll be interesting to see how this coexists (or doesn't) with the normal camera features and look (the picture is hackertastic, in a nostalgic sort of way, but not big on readability).