They are here, Imperial Knights leaked pics and rules. It looks like the rules from 4chan are very similar to these leaked pages from the White Dwarf. Lets take a look.
Sites are now showing off the leaks, so here is your link, and some additional information I have seen. (leaks will flow I am sure, in the next few hours on the Paladin and other rules I am mentioning here. At the moment though, only the Errant and another pic are currently leaked. give them a few minutes)
http://gmortschaotica.blogspot.com/
http://40kwarzone.blogspot.com/
http://descansodelescriba.blogspot.com/
via the leaks on the sites above and some other information I have seen.
Imperial Knights can be fielded as an army. A primary detachment of 3-6 Imperial Knights.
Can be fielded as Allies fielding up to three Imperial Knights as a single allied detachment for each primary detachment in your army.
(no mention yet of Adeptus mechanicus in the White Dwarf leaks)
Knight Errant and Paladin have the same stat lines and are super heavy walkers with the single facing Ion Sheilds 4++, and the invincible behemoth rules.
WS4 BS4 S10 F13 S12 R12 A3 HP6
pts are as reported
Knight Errant has a heavy stubber, Thermal Cannon (36" S9 lg blast melta), and a reaper chainsword (S: D)
Knight Paladin has a Rapid Fire Battle-Cannon, 2 Heavy stubbers, and a reaper chainsword