This could quite possibly preview the mk3 Leon! However, that depends on 2 things. 1. If this car was design under Donkerwolke and not the new chief designer 2. If like the mk2 Toledo, it will share elements of its design with its smaller sibling or become a model in its own right as i have read. (The mk3 Leon has been designed by Donkerwolke).
The IBL is based on the recent VW jetta, but is longer by a few cms. I believe this concept will preview the new Toledo and the new Exeo. Where as the new Toledo will share it's underpinnings with the Jetta/Golf, i believe the next Exeo will take on the recent Audi A4 platform when it becomes available for use but i might be completely wrong.