Actually I have modified our Corolla so that I can tow it with the ignition turned all the way to off. I determined that what activates the steering wheel lock is opening a car door.
What I did was remove the "door open" button on the door jam, so now the computer does not know whether I open the door or not. Now when I prep the car for towing, I lock all the doors except the driver door. I then exit the car. The only penalty I pay for this mod is that the interior light does not come on if all I do is open the driver door. If I open any other door, or use the handle grip or key fob to unlock the car, the light turns on.
For me this is a good solution. Unfortunately when I emailed this question to Toyota they just replied with a politically correct answer that said "don't do anything".