I need to be able to measure the success of implementing Salesforce1 Mobile. Is there a way of reporting on what records were created or updated via Salesforce1 Mobile?
Have you checked out the features in Winter '15? You need to have Salesforce enable Event logging but there is this mysterious mention in the release notes of "Salesforce 1 Adoption" as a file type in the Event Logging featureset. Page 191. This might be what you are looking for.