Migrating from multiple referenced nodes to a field collection

As a part of upgrading http://association.drupal.org to D7, I was also tasked with [url=http://drupal.org/node/1469162]removing the sponsorship sales system[/url]. The old sponsorship system was based on Ubercart, and since most sponsorships are faily high-dollar, they were being managed directly by the Drupal Association financial staff. Thus, no need to have a series of nodes linked together, with Ubercart, just to show which sponsor was associated with which event\DrupalCon\etc.