The official Blu-ray has Seamless Branching too - between the Spanish and English versions of the Crawl - and there is no shortage of projects (or MKV files) based on that…
just wanted to say that i also applaud your choice of release format. i am sure someone will mkv it and that version will also be shared, but it is nice that you are putting out a disk ready version instead of us having to wait for someone else to do it at questionable quality.