I have lots of experience (like more than 12 hours on the water in the last month alone) with the 2010 Rio M. I have a couple of hundred hours on the 2008 Rio M.
I know the new (and the old) Rios perhaps better than anyone.
With a 3.5 or 5.0 m2 rig, you will need a minumum of 16-18 knots of wind (like in the video, but those were not 3.5 or 5.0 m2 rigs for sure) to get planing performance.
What website are you stating has the lovely girl on the Rio S?
I've looked at the Starboard Rio video, and there is no way to tell if the girl is on the
Rio S or the Rio M. Perhaps the board looks a little smaller/narrower, and it could be a Rio S, but no way to tell for sure without checking with the folks who did the 2010 photo shoot.
The Rio S/M/L are basically the same shapes 2008/2009/2010.
Only some minor graphics and EVA deck details have changed.
I ordered a Rio S Sport 2010, but was unable to get one, and I'm a team rider.
Hope this helps,