From Forgeworld Open Day we saw the new Cerastus Knight Lancer model, and finally its now available. It stand much taller than an Imperial Knight, and has its own rules which I have linked down below the break.
Here is a link to the rules, which clearly show that the new lancer can be taken as a Lord of War for any Imperial Faction or is included as part of the Imperial Knight codex. This will give the model a lot of flexibility as to where and how it can be fielded.
http://www.forgeworld.co.uk/Downloads/Product/PDF/L/lancer.pdf
Cerastus Knight Lancer £170.00
Here is a link to the video with Darren Parrwood
https://www.youtube.com/watch?v=uexBp2IE95w&feature=youtu.be