The last guide you provided to help with planning was very well-received by the clients I shared it with. More best practices guides and tools that I can share with clients would be great.
Thanks, that sounds like quite a project! We're not quite at that level of workflow, but we did graduate from Omnigraffle a while back due to responsive design needs. Using Axure allowed us to create versions with breakpoints that we could show in a browser. It would be great to eliminate the PSD stage, but I think I'm a long way from that right now. Thanks for the ideas!
I've used MotionMail with great success (users loved it), but it's MailChimp specific. We are looking at gifcountdown.com for a campaign in another provider, but haven't had a chance to test it yet.