1. Running backs in the first round are a dying species. The NFL is primarily a passing league, so unless you're getting a franchise specimen like Adrian Peterson or some such, it's maybe 50/50 Duke goes that high. I can see a team in the 20's taking him, but Top 15 is out of the question. Also, Gurley will go before Duke, as a point of comparison.
2. What exactly has Dorsett shown that merits first round ability? He can run a 9 route like nobody else in college, but is slight of build, hasn't shown a propensity for running other routes other than the aforementioned, and doesn't show a tremendous amount of "wiggle" in his physical traits. Doesn't get in and out of breaks anywhere near as well as Allen Hurns, and he had over 1000 yards last season and wasn't even drafted. Granted, running a 4.2something at the combine will do a lot for him, and there's a chance someone at the end of the 1st takes a looooooong shot, but again, Dorsett doesn't scream "1st round lock!" to me. He's like Ted Ginn minus the return ability, so unless the Dolphins or the Raiders do something stupid, he likely won't go that early.
3. Perryman is the most likely to go in the 1st, because athletic, hard hitting LBs with good size and instincts don't grow on trees. I agree that he should be somewhere up there, but a lot will ride on his combine and how the rest of this season plays out. Unless he bombs the combine, I can't see somebody like San Francisco or Pittsburgh not taking him if he's available in the bottom half of the first round. He should be starting next year, someone will stick him on the outside and he'll be a terror.