In 1999 Urban Meyer (then Notre Dame's WR coach) and Dan Mullen (then a ND GA) drove to Louisville to meet Scott Linehan and (oh yes!) John L Smith to learn some spread concepts since Louisville was shredding defenses back then. They were so impressed by John L Smith they wound up extending the trip.
Meyer and Mullen stole everything they liked and created 'their own' version of the spread which they proposed to Bob Davie. Davie was reluctant to install it during the '99 season, but they did work towards melding some of Meyer's and Mullen's concepts into the offense for 2000. The turning point for Meyer was when Notre Dame lost in OT to Nebraska (ranked #1 at the time) in 2000. ND WR David Givens went to Meyer after the game crying -- literally in tears because he didn't touch the ball once. Meyer took responsibility for it and claimed it was his own fault for not finding other ways to get Givens the ball.
After that season Meyer and Mullen went off to visit with Randy Walker and Kevin Wilson to find out more about the Northwestern offense that had just won the Big Ten. A lot of people forget how ridiculous Kustok and Damien Anderson were in 2000 (I want to say Kustok had something like 3,000 yards of total offense and around 30 TDs in 2000). That could have been a great team if they had a defense, particularly a defense that got the offense more possessions. Meyer and Mullen also visited Joe Tiller at Purdue.
That was the offense Josh Harris ran at BGSU in 2002.
Between the 2002 & 2003 seasons when Meyer went on to Utah, he spent a lengthy amount of time studying in West Virginia under Rodriguez, who had also done some of the same research Meyer & Mullen did and similarly wound up with a variation of Randy Walker & Kevin Wilson's offense. Rich Rod at that point had made zone-read shotgun-triple his base offense, which had resulted in the 2002 WVU offense finishing second in the nation at 283 rush ypg (behind Air Force, ahead of Navy and Nebraska).
That was what Meyer began running with Alex Smith in 2003 & 04.
Kevin Wilson, of course, is now the head coach of Indiana, having been the OC of some decent 'multiple' spread offenses at Oklahoma from 2002-2010.