QuoteIt's ready when it's ready.I was hoping for a more reliable answer, but I guess that would be too easy... so I guess I'll have to do my own estimation.
There are no timeframes within ML project.
Canon 5d Mark III started alpha around September 2012, never reached beta until early 2015.
Canon 6d is started alpha december 2012, currently in limbo http://www.magiclantern.fm/forum/index.php?topic=3904.0
Canon 7d (not mark II) started alpha december 2012, still in alpha...
So drawing from that info since 70d alpha started January, 2015 this will most likely take much MUCH longer to reach beta and highly likely it won't reach stable release within a reasonable time frame.