If anyone is interested, I contacted Prestigious and arranged to buy their kit and they had an installer in Fullerton CA who installed the kit in my LS=460L yesterday. The kit cost $322 and the install was $100. It works perfect. There is a small module installed on the dash that has two buttons. One is for Nav overide and the second is for DVD overide. Both light up when on (in the overided position). while driving home yesterday, we wathched a DVD and had no difficulty entering an address in the Nav system. While I did not use the phone to dial out, everything lights up on the phone menu when the overide switch is ON.
I realize this is kind of a pricey solution, but for me it is well worth it. It looks to me like there are no wires to cut and the switches are a nice feature.
There is a link in this thread to contact Prestigious.