Symptoms
After performing and upgrade from 4.6.10 to 4.6.11, it appears as if the K2 Designer for SharePoint 2010 list and library wizards disappeared.
Diagnoses
We are not 100% sure how this happened, but the current suspicion is that something went wrong with the upgrade.
Resolution
After we re-ran the K2 for SharePoint 2010 Configuration wizard, the list and library wizards were visible again.