It would be nice to be able to set a function to editable instead of just a boolean.

Here is a quick implementation. I'm sure you can find a better way. I don't have the capability to support a full pull request due to my environment.

var editableValue = column.get("editable");
var editable = _.isFunction(editableValue) ? editableValue.call(this) : editableValue;
if (editable) {

This will allow the user to determine if they want it to be editable based on the model and column.