DON'T force the tilt manually!
In the long run this will probably permanently damage your Kinect!
I don't know if any tool specific for this task already exists.
However, it should be straight-forward to implement some sort of daemon/service to do so.
With libfreenect it is really trivial: all you need is 'freenect_set_tilt_degs()'.
The following functions may also be useful depending on how clever you want this daemon/service to be:
'freenect_update_tilt_state()', 'freenect_get_tilt_state()', 'freenect_get_tilt_degs()'.