just as I came back from my exercising received a message in my skype from a very reliable source.
Like I expected, all of the shown to be upcoming tanks by the Russians are just another hoax so if you see them around you now know.
The Buganov's KV-4 in particular and which work wasn't attributed by the Russian pages, its "Giganaut's" artwork, I have photographic memory and recognized these straight ahead but is pure laziness from the guys not checking something as important as this, a simple Google search on the image brings the guy's work on first page.
Giganaut's work has been featured a couple times in FTR (and that's where I recognized his stuff from) but he actually has a DeviantArt page dedicated to his creations which is worth of taking a look (just ignore the mecha/furry fetish thing going on if that doesn't float your goat, it doesn't float mine for sure but I respect it): http://giganaut.deviantart.com/
And about the IS-152, there exists a similar aberration of nature in real life (and thanks to Andy J. for sharing this!):
Actually no... I remove that thanks from Andy! My eyes bleed from watching that, damn you Andy, damn you! hehe