Not going to happen. For many, many reasons. I'll post one reason but am too disinterested and tired to post more. Other posters can add too it.
Reason 1
If the Broncos use that pick on a running back, whoever it is, even if they are the worst rated back coming out -will rush for more than McGahee anyways-
(in the Broncos offense)
so why do the trade IF YOU ARE THE Broncos?