Whoever comes up with an on-prem Trello that supports LDAP and group management wins the on-prem Trello-like enterprise market. To my knowledge, only Redbooth does this. $30/user per month. Insanity.
I've been using this in a professional context for the last four months or so. It's been pretty good. As well as a kanboard it supports a calendar view, task list view (similar to ToDoist) and a very basic Gantt view (no dependency tracking).
[1] http://kanboard.net/documentation/ldap-authentication