Hi,
How about a switch or servo that will make the head move in any direction and just use a motion sensor to turn on the head. Anything like that?
I get the feeling that you are maybe not equipped, enabled or wanting to do any programming or electronics building?
If that's the case, your options are a bit limited, but where there's will, there's way

It would probably be a god time to let us in on a few things:
Can you read a schematic and build from it?
How about programming?
And your mechanical skills?
The parameters of the room and head, like...
Size of room?
Head placement (in the room and at what height)?
Needed distance of reaction?
Available power source?
How much control do you have over the room (in terms of eg. installing sensors in the floor or at room entries)?
Feel free to fill in other specs that you may think matters.
Without this knowledge, most advice will be like hunting ducks with a 12-gauge and a blindfold - inadequate, slightly risky and a waste of gun powder.
Would something like this work?
http://www.elechouse.com/store/index.php?main_page=product_info&products_id=294
To get the PIR to reveal a persons relative placement, you have to spin it or sweep it like a scanning RADAR, as it only tells you that it detects a certain temperature gradient within its field of view.
The exact position of the spinner/sweeper has to be known at all times, to relat the detection of body heat to an angular position.
The product in the link could be used as part of such a device, but I think you could find a cheaper alternative (again, this depends on what you're willing/able to do).
http://www.elechouse.com/elechouse/index.php?main_page=product_info&cPath=72_74&products_id=276
I gather that you think of the "Sensor Shield V4.0"?
This alone will do nothing, it's an extension unit for an Arduino microcontroller board, which you need to have to use it (plus you need to program the Arduino).