Not sure if anyone's mentioned it yet, but there is a list over on GameFAQs that has all the sleepers in each draft listed out.
http://www.gamefaqs.com/console/xbox...e/958702/57545
Don't be discouraged if you draft someone you think is a sleeper and he comes out as a 50-60 OVR. Look at his potential and his position ratings. I've drafted quite a few guys from the Madden classes who were dumb as a rock (20-30 AWR), but had A potential and 80+ in all their position ratings. I went ahead and started them because AWR doesn't mean much anymore. They dominated.