I bet on the new iPhone, G4 or HD, that the mulitasking GUI will not cut the top row of applications and service bar off. The new phone will have a higher resolution and will simply resize the screen to allow the pop up multitasking dock.
Interesting, but I don't think that is how it is going to be. I am guessing that the GUI will be the same on the new iPhone as what was shown during the keynote.