Just read that this new ruleset has been released and is now online
https://imperiusdominatus.org/
Essentially an adaptation (I think) of NetEpic Gold (previously Space Marine) to fit with the 30k setting and the Horus Heresy.
Apparently it's based on the Forge World red and black books in terms of units, compositions etc.
Miniatures-wise I assume Vanguard and the numerous self-print or printing service options will cater for it.
It's been developed by a chap who has the handle of Primach (who I believe was responsible for the NetEpic Gold ruleset) and has been in development for some time.
All the rules are free to download as are the unit and formation cards (it uses a similar system to Epic Space Marine)
Just the marine legions available for now but apparently Orks are next and on route.
Looks very interesting! I love Epic Armageddon but the granularity of special rules, assault etc. means that a faster set of rules would help with really large games. There are some MEGA sized infantry and tank companies listed so looks like these will come into their own!
Will keep doing some reading and post any other news about it that I find.