Sony will have a lite version, this is the design for MS's lite version. Its also what will go into OEM brandable products.
The lite version for both Sony and MS is what comes out this year. The 'Next' versions, the powerful ones, will be based off the lite design BUT with extra SoCs..
Lite in 2013
Next in 2014
Your source? You seem like you are pretty sure that will happen rather than making a prediction.