[gadders]

This is pretty good if you want an actual personal Kanban board: http://greggigon.github.io/my-personal-kanban/

I use it for my to-dos at work.

[nextos]

I spent a lot of time thinking about kanbans, only to realise org-mode can be very easily turned into one.

And IMHO an outliner is much more flexible than a webapp.