Note: I do not advocate replacing Stafford. Please read post before making comment.
This is obviously not to replace Stafford but I think drafting a 4th or 5th round QB to be our primary backup could be a solid move. It seems that every year a 1st or 2nd round QB seems to free fall into a later round ('10: Ryan Mallett, '09 Colt McCoy, etc.). Now granted my examples only fell to the third but this year the guy I am looking at is Nick Foles.
Dude is 6' 5" 240lbs and entered the season as the #1 senior QB. Now he obviously had a down year and his stock took a hit, but with measurables and the ability that he displayed in college he is at worst a solid backup in the NFL and in the 4th round he would be a steal along with being far cheaper then Shaun Hill or Drew Stanton.