Just a small side stat note - on the significance.
39 of the 57 SB Winning Teams had a starting QB drafted by the team they won with. 32 of the Team QBs* were drafted in the 1st round (not necessarily at the top of the round).
*note: For stat purposes I chose the QB who played the most games in season not necessarily the SB Starting QB, thus Schroeder over Williams. In a tie situation I factored in the post season, thus Dilfer not Banks. Also I counted it as a home team draft if it was a draft and trade/acquire situation. Thus Elways was counted as a home team draft pick even though drafted by the Colts. The 15 Broncos count Manning as a Hired Gun QB for their SB victory.
To me, it seems rather significant though not critical.