The steady drumbeat of exclusive signings by the Big Two continued this week as Marvel inked artist Paolo Rivera and writer Dan Slott to exclusive contracts.  Rivera is noted for his lush painted covers such as those he did for the Sabretooth mini-series, Iron Man and Silver Surfer.  Slott's writing credits include: Venom: Sinner Takes All, Ren & Stimpy, Arkham Asylum, She-Hulk, and most recently the retro Spider-Man/Human Torch mini-series, which ends in May, and the upcoming G.L.A. (Great Lakes Avengers) series that debuts in April.