I just happen to notice things like this, maybe it is just me.
In the DetNews there is a fluff article on Harbaugh that is a reprint from the San Jose Mercury News (http://detnews.com/article/20101230/SPORTS0201/12300434/1131/sports0201/%E2%80%98Uncontrollable%E2%80%99-urge-to-win-at-everything-drives-Jim-Harbaugh) regarding Jim's desire to win. In the article there is an anecdote about when Bo walked into his office to find Jim, 9 years old at the time, sitting in Bo's chair with his feet up on Bo's desk. While the story is amusing, it also shows how much exposure Jim must have had to the program at that young age to be so comfortable that he had his feet up on his Dad's boss' desk.
Additionally, at age 9 (having been born in 1963) he would have been intersecting the program at the same time as Dave Brandon ('70-'74). While those two would not have been hanging out in the bars at that time, I am sure any member of that team (Brandon included) would have watched Jim at Michigan very intently knowing how the old ball boy became the star QB. Particularly an alum like Brandon who has stayed in the Detroit area for his professional career and would have more access to the program when Bo was coaching.
While I previously believed there were probably back channel discussions since they were ex-players, I am only more convinced knowing this new fact that these two probably have had more than just a few casual conversations. I don't propose to know what happens to RR post-Jan 1, but I am pretty sure Brandon knows Harbaugh's position and what his choice will be. There are too many connections for this to not be the case. Either way, we will have a good coach come January.