"locked" iPhone video playback mode for children?

After we upgraded to iPhone 4, one of our old iPhones was pressed into service as a children's video playback device for our 1.5 year old. That's one of the best things about an iPhone upgrade -- every upgrade comes with a "free" previous-gen iPod touch!

And, well, The iPhone is the ultimate kid-pacification device. With one caveat.

He does well holding it, most of the time, but tends to push the home button or accidentally activate enough touchscreen controls to stop video playback at the least or kick out to the home page.

Is there any way to activate a "locked" or "children" video playback mode on the iPhone, where accidental button presses don't stop video playback?

One possible solution would be to use a locked Pelican Case - clear, much tougher to break and with a headphone jack pass through.

always the jailbreak route. Here is a demo of an app (IncarcerApp?) that does that, locks it. I would love it as my 1.5 yr old does the same thing :) http://www.youtube.com/watch?v=4ysRou_kvOo&feature=related

Apple finally announced this as a feature in iOS 6, you can disable the hardware buttons and even parts of the screen by using Guided Access.

"We were surprised at how many kids with autism have been using the phones, but there are controls in apps that you don't want them hitting." You can now select parts of apps to disable.

All phones back to the 3GS (but not earlier..) get this feature.

Nope, unfortunately. Apple are incredibly strict about the behaviour of the home button: whenever it's pressed, the active app will terminate immediately (or move to the background on iOS 4) and you'll be returned to the home screen.