Thanks for taking a look at it, Alex.
Your suggested approach to the Done and Next columns is actually probably more consistent with the version of personal Kanban typically implemented using sticky notes (!). I hesitated to do it that way because, at least for my setup, the next and done lists would both be huge, and for me personally this is about having a filtered view of my tasks-in-progress. I could make that an option, but I would first need the functionality to set options, so that's something for future versions.
I could also use the list tag that you suggested to generate a dropdown list of lists that use it, and then the user could choose from it.
Rebecca