Simon, * Though it does not have properties for clipping, Webkit's proposed implementation of 3D CSS does have them for perspective. Clipping, lighting, texture stretching and additional considerations could also be a part of that spec, but those are discussions for the CSS WG.
Without a 3D media element, none of that work can be done. * This proposal of a model can be considered a direct 3D analog to a PNG, and its height and width could certainly be modified in the X-Y axes on which 2D elements live, affecting document flow in that fashion. * Webkit's implementation of CSS does not remove 3D-ified elements from the document flow, the perspective of that flow is merely changed only for the affected elements. 3D and 2D elements can exist side-by-side that way as well. -Brian