I have an application running on AppEngine that uses about 50 CPU hours a day. Most of it is spent waiting for the datastore.
I am contemplating moving it off of AppEng
If you can redeploy to appscale, you won't have to rewrite any of your App Engine code.
You can use TyphoonAE, which is based on the SDK, and designed for small to medium scale deployments - eg, individual servers to small clusters - and should be fairly easy to set up.
Sorry to see you go.