This is the Berserk Boris figure from Heresy, heavily converted for use in Blood Bowl. I'm enjoying sculpting wih greenstuff, even if it can be frustrating; It's like trying to sculpt with chewing gum.
I'm finding that a sewing needle with a tiny amount of cooking oil on it (and I mean a TINY amount) is a great sculpting tool. Greenstuff is still difficult to use, in my opinion.
Oh well, at least I can rely somewhat on my painting to hide any crappy sculpting.