Is it possible to avoid the .html.md in the Markdown filenames?
I would like to use:
Short answer: no.
Long answer: You can use renderSingleExtensions option - see http://docpad.org/docs/config - however that will render my-post.md to my-post.md instead of my-post.html as it is not aware of the extension.
The issue is this, things like coffee can be rendered in different ways, for instance to js using coffeescript or html using coffeekup. We can also want to bundle extension rendering, e.g. html.md.eco. Therefore any ambiguity here is a dangerous.
One option however is to add an extension mapping option that allows us to alias extensions, however that seems like a lot of effort for little reward. If you're importing from another system, it wouldn't be that hard to write a script to rename your extensions.
Give all this, such functionality isn't on our roadmap. I will keep it in mind when considering future architecture changes though. Thanks for the report, closing for now.