Does anyone know of an app on the Android market that disables buttons during a phone call?

I have the “Toddler Lock” app, which lets me give the phone to my daughter while I’m changing her diaper or whatever, so that she can’t call anyone – but it doesn’t work all that well, because all she has to do is hit the hang up button, and it locks my phone, then she gives it to me to unlock, and the cycle repeats… but that’s not really the point. That’s just an example of what I am talking about. All of the buttons except for the hang up button are disabled, and the only way to close out of the application is to touch all 4 corners in the right order.

Is there an app that will allow me to give the phone to my toddler when someone wants to talk to her without me having to call them back when she accidentally closes out the call? Maybe something where you have to hold down a certain key or something to unlock all of the buttons again?