iOS 4.3 multitasking gestures hacked onto iPhone 3GS

YouTube user antoninygaard seems to have been able to go into iOS 4.3 beta and manually enable the multitasking gestures meant for iPad developer testing (as well as the mute/orientation lock toggle!) We heard Apple was testing them internally but he's got both running on his iPhone 3GS.

We already know Apple won't be giving them to end users for iPad much less iPhone any time soon but check out the video below and let us know what you think. Are the multitasking gestures usable on a screen that small?