CBS sports seems to be the best prospect ranking site around. Obviously it's not perfect, but a lot of the time is pretty accurate, and is powered by nfldraftscout.com. The information they use is coming directly from NFL scouts a lot of the time.

This is still subject to change because next year's draft is still a year away. Jamal Williams is coming off an injury, which is factored in, so he assuming he stays healthy his value is likely to increase.

Jamal is rated as the 15th best RB prospect for 2016 right now and 23 RB's total were taken in this year's draft. So right now it's looking good that he ends up drafted.

They also have,

Bronson Kaufusi as the 4th DE (23 were drafted this year)
Taysom Hill as the 26th QB (7 were drafted this year)
Mitch Matthews as the 50th WR (34 were drafted this year)

It appears likely BYU will have two players drafted next year.
It's also interesting to note Devontae Booker is the #1 ranked RB prospect next year.

http://www.cbssports.com/nfl/draft/prospectrankings/2016/RB