Onstar privacy handset???

Hi all...
Does anyone know if you can get a handset for Onstar? Onstar is great for personal calling but sometimes it is hard to hear or you need some privacy from other people in the vehicle. Has anyone tried to, or installed a Motorola handset? Any ideas would be great to try to figure out how to make it work. Thanks...

If you have a digital OnStar system and a Verizon cell phone you can get a plan to share your airtime and phone number with your OnStar personal calling. Then you can transfer between your regular cell and OnStar.