I'm able to view my Card Preview in https://cards-dev.twitter.com/validator .
My whitelist request is pending approval since 12th September 2014.
I get the following in Log -
INFO: Page fetched successfully
INFO: 19 metatags were found
INFO: twitter:card = summary_large_image tag found
WARN: Not whitelisted
Please let me know what I need to do from my end to get my domain approved and start using twitter card
Thanks and Regards,