Doesn't this look a bit closer to W7P's navigation? I don't remember seeing that kind of interfaces on webOS (may have missed it of course) but having the "next" screen "leak" into the current one is a prevalent pattern of W7P, it's a major feature of "panorama" navigation[0][1] (and more toned down but still present in "pivot" navigation[1], where only the title/top of the screen leaks, but the content part isn't leaked)

[0] http://msdn.microsoft.com/en-us/library/ff941104(v=vs.92).as...

[1] http://msdn.microsoft.com/en-us/library/ff941098(v=vs.92).as...