I'm trying to think if I've ever seen a #11 at quarterback since I started following the Huskers . . .
Became aware of football in 94, so in chronological order:
15 - Frazier
18 - Berringer (Simply because of him, #18 has always been my favorite QB number)
7 - Frost
12 - Newcombe
7 - Crouch
5/10 - Lord
12 - Dailey
13 - Taylor
9 - Keller
12 - Ganz
If Spano has #7, Witt has #6 (hate that number for a quarterback), and Lee has #2 (hate THAT number for a quarterback), then I nominate #3, #11, or #19.