Over the past few days some of us have been discussing the aims and ambitions of this project:
There are a lot of pieces to be developed to support this properly. My aim is to get something simple in place to allow blocks, regions and panels to be served out of an ESI cache. There are further ideas to build some sort of ESI-assembly into the Boost module, and to implement an intermediary cache layer between Drupal and an external ESI cache (e.g. Varnish) to prevent multiple bootstraps.
So, let's take this discussion out to the wider community!