Trading back that far creates a real risk of a complete dissaster happening. You would have to have like twelve guys your interested in and hope one of them lasts through the first round. And trading back that far for just a third round pick? I remember Cleveland trading back into the first round for Brady Qunn and I believe they gave up a following year's number one to do it. A team would have to give up at least their round 2s this year and next plus that 3rd round pick to even consider it.
And a wise GM once said if you like a guy and you think he's going to be a pro-bowler you don't wait and hope to get him in the round he is rated for.
And I would bet the house your going to see a Running Back in this year's draft as well as an OLB prospect.