Have really wanted to look at making WP into a static site generator. Have too many clients using WP that could be using it as a static site but won't move away from it... So the admin backend / familiar publishing interface but generating it out to something that could be dumped into S3z
Some people have done variations of it but not well or easy. Is easy enough to trap events that should trigger page regeneration. Just haven't taken enough time yet.
The AWS CLI has extremely amazing performance, having something that could leverage that kind of multithreading for publishing would be great. Especially for the initial site publish.
If anyone is interested in working on this project or taking it on (I'm happy to contribute ideas and/or money) feel free to reach out. mike503 at gmail.