It’s great to know that https for custom domains is on the way. I wish Google would say about their upcoming products _when_ they will be available. For example, that post you sent me to is nearly 4 months old. When they wrote it, did you expect it to take 4 months to become available (considering that they started testing it at the time?)

I already have the feature request about DKIM starred :) But now that I have a solid implementation with Amazon SES and task queues, it’s low on my priority list.

Thanks again

It is currently being tested, see the following announcement:
http://googleappengine.blogspot.com/2011/10/app-engine-ssl-for-custom-domains-in.html

Re: 3 .Outgoing emails cannot be signed

Consider starring the following feature request:
http://code.google.com/p/googleappengine/issues/detail?id=3161