DSi with one or two touchscreens?

[Soma]

I hope it doesn't has two touchscreens, because then the DS Lite would become obsolete. The whole idea of the DSi was to be a third pillar, not a new system so it doesn't make sense at all..... but thinking about it, the DSi will offer gaming capabilities with the camera, right? That's like having two touchscreens because it will then has some exclusives not able to play on the DS. And, does someone knows if it will be possible to play games of the DSi on the DS?