This is a drawing of the 2004 Lusitano stallion, Alvarinho Interagro. He's in the 2010 Lusitano Collection Auction, on this page.
I have a speed paint video of this, but I found out that my camera was set on 70% quality and compressed it to absolute ugliness! I-i
This picture took around three hours; I'm still slow at it. It was also done entirely with a mouse, I don't like tablets.
I might do a request thread, but I'll see what kind of time I have.