I was just listening to 
episode #254 of the Risky Business podcast and heard its interview with the owner of 
Exploitable Labs. EL offers a service to assess people's Web and network penetration testing and report writing skills using 
24-, 48-, and 72-hour online pentesting labs. It's not a certification like the 
OSCP or 
CREST; instead, it's an in-depth evaluation intended to discover a pentester's strengths and weaknesses. EL's service is intended for organizations to verify the skill level of employees and job candidates, but individuals also use the service to test themselves and learn in what areas they need to improve.
People who are very interested in the OSCP certification will probably also be interested in looking at the pentesting skills challenge from Exploitable Labs too. Listen to the podcast interview for more details.