So nobody yet has answered the original question.
Here's what I came up with:
Barring a miracle, Ginn won't be Newton's leading receiver. That'll be Greg Olsen, who currently has 28 more receptions and 300+ receiving yards more than Ginn. Although Olsen is a tight end, he'd still be considered Newton's top receiver.
So we could instead rephrase the question in two other ways:
1. Has a WR ever been the top WR for both a Heisman QB and NFL MVP?
2. Ginn may very well end up being Newton's top TD catcher. He's 3 up on Olsen right now. So we could ask, has anyone ever been the top touchdown recipient for both a Heisman QB and NFL MVP?
In the Super Bowl Era, the answers appear to be 1) Yes and 2) No.
Jack Snow was the leading receiver for both the 1969 LA Rams and MVP Roman Gabriel, as well as the 1964 Notre Dame Fighting Irish and Heisman winner John Huarte. However, Snow only led the '69 Rams in receptions & yards, not touchdowns. So (although it's kind of convoluted with the TD qualification), Ginn would be the first player in the Super Bowl Era to catch the most touchdowns from both a Heisman winner and NFL MVP.
Great John Huarte Fun Fact: Some of you may know that 'back in the day', each season the NFL Champions would play against a team of College All-Stars from the previous season. John Huarte was the MVP of the 1965 game in which the All-Stars defeated the Cleveland Browns, who were the 1964 NFL Champions. That, of course, was Cleveland's last professional title.
Snow, who died in 2005, was the father of former MLB'er J.T. Snow.