I think the Lions are in a bad spot for picking a player at need for this team. As of right now, it looks like OT, DE, and the #2 WR and #1 RB could/should be available at the #13 spot. Since the Lions main needs are CB and OLB, I feel like trading back into the late teens or early 20's would be ideal to land such players as Akeem Ayers or Jimmy Smith at a pick where they are the BPA.
Here is a list of teams that could be looking to trade up:
#14. St.Louis - It is known that they need a big time WR like Julio Jones to have for Bradford. Since its only a one pick move, I could only see the Lions receiving an extra 3rd rounder at most.
#15. Miami - If Julio Jones is gone, the Lions could possibly look at Mark Ingram, but with Miami in need of a top RB, they could possibly want to jump in our spot to take him. Could only see us receive a 3rd and possibly a future pick.
#17. New England - This is the team I expect to want to move up the most if Julio Jones is available. They need a deep threat and a big play receiver so they could offer a great deal. I could see them offering their #17 and either their #33 or #60 (2nd round picks).
#26. Baltimore - They brought in Boldin and Housh, but all of their WR are possession receivers. So if Julio is available they could make this move. One big play WR could make them legit Superbowl contenders. A lot would be needed to move up 13 spots, so possibly #26, #58(2nd round), and #122 (4th round).
Their are obviously other teams that could want to move up, but these are the teams I expect to want to make a move the most.