A year or so ago there was a big push by Sunny Hirai to add Android support to Slate, however after putting in months of work Slate underwent a huge rewrite that more or less invalidated all the work put towards adding Android support.
As you can imagine adding android support to a framework for building rich text editors is a huge amount of tedious back-breaking work riddled with edge cases. Now that Slate has started to stabilise Sunny is raising funds on KickStarter to add Android support back in.
If you are using Slate or know a company making heavy use of it please consider pledging some money (Link below). There is only 15 days to go and it needs 20K more - that's only three low tier corporate sponsors! I'm not affiliated with Sunny in any way, I just really enjoy using Slate and I think Android support is crucial for the long-term viability of this project.
https://www.kickstarter.com/projects/sunnyhirai/add-android-support-for-the-slate-wysiwyg-editor