As we get closer to draft day it looks more and more likely that we might be in no man's land at #11. If Everette Brown, Brian Orakpo (cooling on him - why has he not learned even a good spin move?), and BJ Raji are gone before we pick, the trade down plan becomes more viable. Especially if one of the two top QB's and/or one of the top LT's are still on the board. Right now we're good to go at both positions. Now I might be crediting more flexibility to the Bills front office than is realistic, but I hope not.
If OBD wants Mack or Pettigrew then a trade down to no later than #21 should land either one.
However, as wpod over at the Range posted earlier, we could get very creative if the draft plays out right. Here's his scenario. Trade down with Tampa to #19 if a top QB is still available at #11 (probably Sanchez). We get Tampa's second round pick. They want one (we're assuming that Garcia leaves). Then immediately trade down again with Atlanta to #24 so they can jump Philly and take Pettigrew. They want him. We get Atlanta's third round pick. Now we have the 24th pick, two 2nd round picks and two 3rd round picks! I know, a dream scenario. But I love it. The mind boggles. We get Mack, Coffman, etc, etc. What an adrenalin rush!