Sure, people make dry stouts much like Guinness. I make one that's something like 10% roasted barley, 20% flaked barley, 70% pale malt and mash at 148-150F, IBU ~45. It's nice and dry, and the flaked barley helps with head and gives it a little creaminess. Low to moderate carbonation. I'd think with the rice it would be very thin and dry, which may throw off the balance. It might seem more bitter and less smooth than what I have described.