I’d like to announce a new package for mobile manipulation planning! http://wiki.ros.org/move_base_to_manip
The simple algorithm calculates a robot base location so the end-effector (EE) can reach a desired pose. The method is computationally fast (since it depends on a MoveIt! Cartesian motion plan), simple (~300 lines), and easy to use (requiring just a service to provide the desired pose). There is a basic example included.
Below, the first image shows a mobile manipulator which is too far to grasp the object of interest. The desired EE pose is shown in green. The second image shows the freshly-calculated base position (red cube) which will allow the robot to reach that pose.