Is it possible to add a CiviCRM API to the Webform CiviCRM integration module and how would I do that?
I found this old link for plans to add arbitrary api calls to the module, but it doesn't appear to have ever been implemented:
http://forum.civicrm.org/index.php?topic=22304.0

But it appears that I could use hook _webform_submission_presave to execute the api call when the webform is submitted.