I'm a bit late to the leaked news about the 5 TB Western Digital drives in the beginning of December 2012, however in my defence, I got bored of searching for "4 TB" and "5 TB harddisk" all the time. What's interesting though, is that according to the leaked documents, 5 TB is nowhere near yet. We'll have to wait till the end of this year. From the Samsung/Seagate camp I still find nothing.
As mentioned earlier, a 4 TB five platter (5 x 800 GB) was released in the WD enterprise class line, while a 3 TB three platter (3 x 1 TB) came out in the Red series last autumn. This should have made 4 TB four platter and 5 TB five platter disks the next logical conclusion, but for some reason we'll have to wait another year. With only a single competitor in sight, which doesn't even have an offering, it is hard to not blame the harddisk duopoly for the lack of progress.
Maybe the most interesting part of this news is that some sites have started to speculate in 1.25 TB platters. That is; would a 5 TB drive use five 1 TB or four 1.25 TB platters. According to xbitlabs, the five platter technology comes from Hitachi, which might explain why we have not seen it in a WD drive before. However, now that they have merged (or acquired), that is a possibility. As far as I can tell, 1.25 TB platters are still under development, but when they come out, the potential is for a 6.25 TB (5 x 1.25) drive. Let's hope we will not have to wait yet another year for that to happen.