What I would do?
Nothing really. He could be the league's best running back, or he could blow ACLs in both knees on his first play. Or he might be overwhelmed with the defensive speed in the NFL and be at best, an average back. Not that I think either of those things will happen, my point simply being that even as good as he is, he's still an unknown, still untested in the NFL and thus, he only deserves to go to teams that have a legitmate shot at him without messing up a currently good and cohesive team.
If the Steelers draft goes as well as their last few drafts, Bush is irrelavent because as defending champs returning with nearly all our starters (losing only a few during free agency), how much better would we be with him as opposed to other needs? The difference would be very minimal. Say, to put a number to it, 99.5% vs 99%. Would you really blow the bank for that extra 0.5%?
The way drafts work is to maintain parity in the NFL, or at least attempt to. Teams that blow multi-season draft picks to move up the list that high to take one guy only wreck their teams. Besides, even if we pulled the trigger, I doubt we have the cap room to sign him.