GPS Device

We are an IT & Engineering company. We are looking for a GPS device with a counter.
Basically its for one of our client. they are Lawn movers and they want to mount this system on their machines so that they can track where the machine is and how long it has been used.
 The device should have own power supply as we want to track the machinery even if its not in use. We also want to attach a counter that will calculate how long the machines has been used.

If you have device for this kind of operation please let me know. We have developed several GPS applications for ship tracking, vehicle tracking and so on. We have supplier from China and he dont have any stuff like this.

So if you are interested please let me know. I can be reached skype : 
Regards,
Pauras