The RFC for BGP Large Communities has just been published;

https://tools.ietf.org/html/rfc8092

There is also a draft discussing their use;

https://tools.ietf.org/html/draft-ietf-grow-large-communities-usage-02

There are more details on the BGP Large Communities work and an implementation tracker at;

http://largebgpcommunities.net/

BIRD 1.6.3 support it, so I'd like to suggest we think about a third route server for testing with BGP Large Communities.  If that goes well then phase it in with the production servers maybe toward the end of 2017 when more of the implementations for big iron routers make it in to production code,