I just created a public Kanban board on waffle.io for rs.js development and did an initial run of triaging our current GitHub issues.
It has various columns that gives you visibility into the state of our existing GitHub issues. There's a backlog, "planning/discussion" for things that are being discussed, "ready" for actionable issues that you can just start hacking on anytime, "in progress" for things that someone started work on, and "done" for closed issues.
The good thing is that you never actually have to use or care much about the board if you don't want to, as it's just using GitHub issue labels for determining the state. Those work both ways, so when you move an issue to a different column on waffle.io, it will just add/remove the tags accordingly, and when you add/remove tags on GitHub, the issue will be moved on the board.
Please let me know on IRC, in case you want to propose edits to the columns. Thanks! (All core contributors should have full access to all settings and such already.)