take this one with a pinch of salt for now, it seems as if Sony is working on another VAIO P range of mini notebooks/netbooks. According to Sony Insider we're looking at two different SKU's as well, not counting the colour options.
First up is the VGN-P710T which is said to be available in black, red, green and white, although no other specifications are really known at this time. Then there is the VGN-P730A/Q and VGN-P730T/Q both of which throws a spanner into Sony's current model number, unless there's a colour that we're not aware of that starts with the letter Q.
It's anyone's guess at the moment what Sony is working on and what changes will be made, but hopefully we'll see slightly larger models as the VAIO P 500-series is a little bit on the small side to be functional. It's also anyone's guess when these new models will be out, but we'll keep an eye on this and will post an update as soon as we hear any more information about it.