Broncos have 2 late 1st rounders, they might give up both to move up, but I doubt it (and I don't think GB wants to drop all the way into the 20's). It seems to me that when teams move up, it's 3 to 5 spots, swap 1st round picks, and get the 2nd round pick from the team moving up. So GB could theoretically drop to 8-10, and pick up pick 40-42 or something like that.
I also seem to remember a couple teams dropping 2-3 spots in the 1st to gain a 3rd round pick. All depends on how motived one is to move up and the other to move down.