Earlier quoted context omitted.
Good news! You can now scratch your own itch on dotCloud. We've added support for custom builds, which means you can run Tornado, Thin and any other asynchronous web server you want. We're planning a blog post about it the coming days.
Except if you scratch your itch on dotCloud, you can't run it on your own laptop like you can with Cloud Foundry Micro or on other services that might have a better interface like AppFog. That's the problem with contributing to a closed source project.
[1] https://github.com/qpleple/wordpress-on-dotcloud [2] https://github.com/jpetazzo/thin
At the same time you mention in your blog: "Appfog has secret sauce that we did not contribute to the open source project, ways to optimize PHP and the experience around PHP".
For the sake of openness, I encourage you to share your secret PHP sauce as a custom dotCloud build. There's a whole community of hackers doing the same.