Support for sign-in & sign-up via OAuth resource owner

What is an e-commerce solution without the possibility to sign-up ad-hoc via a user account from an OAuth sign-in provider (eg. Login with Amazon, wich is particularly suggesting in the case of Sylius' application domain)?

I already began to work on a reference implementation for an OAuth support in Sylius by using the HWIOAuthBundle: https://github.com/headrevision/Sylius/tree/oauth-login

(so far the OAuth sign-in is completely separated from Sylius' native sign-in: http://t.co/TCZ5tZ0s0K)