Looks like the only option is to draft OLB's out of college if the 3-4 defense is being used. Every attempt I have made to switch a DE to OLB has caused WAY too much of a drop off in ratings. The way progression works I'm guessing we'd be much better off sticking with college LB's to fill the OLB role of the 3-4?
Now at the D-line positions, I think we can draft either bigger DE's or DT's to fill those roles as both ratings seem to transfer for those positions.