Our guidelines are shifting to dictate that all public web properties be responsive design so this is a must. Especially with Apple's release of Handoff this has to be something that is released today vs. future roadmap...subscribing.
I wanted to update this thread, as I know many of you are anxiously awaiting news regarding responsive landing page enhancements. We're making great progress and should have a release date to share with you soon. I will make sure to update this thread when there are some more details to share. Believe me, I am as excited about this as you are!
Also, I'm currently soliciting additional feedback from customers that might be willing to have a quick, 15-minute phone call to discuss landing pages. If you're willing to chat, please drop me a line at email@example.com.