I've just released on open-source project: ELPA on AppEngine. This is an implementation of ELPA written in the Go programming language, that runs on AppEngine. Right now it isn't ready to be a real running system, but it probably won't take too much work to get it the rest of the way there.
It might have the possibility into being a really cool ELPA that is open to all, as opposed to the other ELPAs which are hand-curated. I'm still thinking about where I want to take this.