I've actually used the above tutorial for another project that was using elasticsearch. It's not incredibly difficult to implement. I would do it as an add-on but I've avoided ElasticSearch add-ons for two reasons; 1) smaller market, not everyone has it or can have it, 2) I don't have a server handy for elasticsearch as I don't use it for anything on a personal level.
If someone needed assistance getting this going or is interested in funding the development I'd be open to do it. The biggest flaw to this is the fact you have to rebuild your entire search index after it's implemented due to changing the index analyzer for fields.