Extending kibana

We are starting to use ELK for analytics and hitting against some limitations with kibana. Particularly there are times where we need dashboards to contain multiple time-frames, graphs to contain composite of multiple queries, percentages that relative to each other, etc. We would also live moving averages (that are coming natively - https://www.elastic.co/guide/en/elasticsearch/reference/master/search-aggregations-pipeline.html) - but we could calculate that ourselves, but then we need a way to preprocess the output from ES before graphing.

I see that Kibana 4 is all written in Angular and D3, which is great. I don't know if it would be easy to import something like http://krispo.github.io/angular-nvd3/ I'm wondering if there are other people extending kibana in this way that have pointers? Or if there are active kibana forks that give some of these extra features?