Hi,
There is not a standard evaluation "service" yet but we are working on that. We do have agile assessments for the team and program (team-of-teams) levels posted on our SAFe Reporting site that can help with self-assessment but this is admittedly an assessment of how well you're doing with agile, not your readiness to embark on an agile transformation. I'm happy to work with you to explore some ideas I've generated through work with customers.
Amy (asilber@us.ibm.com)