It exists - but it basically boils down to a few things
1) Black voter turnout drops from 66 to pre Obama levels of 60% (expect this to happen barring something big happening)
2) Non college white turnout goes from 57%to 62%, and moves from 62% R to 65% R
(Based on the % increases at the GOP primaries, the 5% jump is what would be expected for Trump)
3) Latino turnout is mostly concentrated in states that are fiercely R or fiercely D, so increased turnout does not help Dems very much
4) College white voters break 2% more towards Trump
http://projects.fivethirtyeight.com/2016-swing-the-election/
The link is a really cool way to model the election. Basically, if 4) happens, Trump wins. 1 and 2 are currently what should happen based on the primary turnout and voting.