That's what I was thinking. At first glance it looked to me like the back of a hooded Maul, but upon increasing the size of the picture it does not look that way so much. Honestly, I can't make it out. I'm thrown off by the uncovered Maul silhouette of the half scale bust they showed us, and the lack of noticeable pointy forms on the covering fabric where the horns should be. Could it possibly be a different half scale bust they have not mentioned or another statue? What would that lump sticking out could be towards the lower part of the covered piece?
Edit: Giving it a second look ...Hmm, it does look again like it may be the half scale Maul bust turned sideways? That triangular lower stretched out area of the fabric looks like the pointy ends of the shoulders on an arm-less bust ... I'm thinking again it could be Maul