Tablet talk app for the ipad

There was a previous thread but no real answer ont his topic.

I need an app like tablet talk for ipads. I need to have my ipad communicate over bluetooth with my iphone, to send and receive sms and phone calls via my iphone - essentially enabling my ipad to act as a bluetooth device for my iphone. The reason is my ipad is my in car radio/multimedia device (it is the source). I know many others doing the same and looking for a solution. I have heard mixed responses about it, but I understand it is possible, right?

So if it is indeed possible, who can develop this and where do I take it?

Any help greatly appreciated.