This project would consist of the following parts.
Because of the amount of work and how the workload could be split I think it would be possible to go with a relatively large team.

* Extending the Magento REST API to supply all required informantion with Guest level authentication
  - All products, incl. hidden simple products that are used in configurables and bundles
  - All options and labels of attributes that are used in the layered navigation and in the product listing
  - All categories
  - Product to category mapping
  Focus on cachability and update when a products salability status changes.

* Building a set of angularjs directives
  - Layered navigation attribute filter
  - Layered navigation category filter
  - Layered navigation price filter
  - Pageable and sortable product list (maybe also a grid)
  All angular directives should use "transclusion" (gotta love that word) they can be themed.
  Localization using angular translate would be cool but probably could be added later once the base functionality is working.

* Building big test data - ideally this is a "joint-venture" with the "Real Big Sample Data" project.

Fast client-side processing of 100k products and 3k categories would be a target.