A new model found from Games Workshops "What's New Today"? Quite possibly, as it looks like a new model, or one that I am not familiar with. Not my find though...... Steve the Warboss, pointed it out during the latest discussion. Check out the mode circled in the image below.
(all images are from What's New Today)
The image can be found here on What's New Today
this may have been in the leaked images, or a conversion of sorts, but looks new.