Next generation Grand vitara will use stretched version of the Kizashi platform

Suzuki is said to be working on an replacement of its Grand Vitara. The new SUV would show up in 2013 and be based on a stretched version of the platform underpinning the recently-unveiled Kizashi midsize sedan, which is expected to hit American showrooms for the 2010 model year.

the current Grand vitara (codename YK4) is different from MK1 and MK2 Vitara as 2 early GV use truck like ladder flame platform but MK3
Grand vitara is newly deveplope by Suzuki engineer is use Monocoque technic but suzuki engineer are add additional strengthening elements to provide the rigidity needed for serious off-road driving.

source http://autoten.com/2009/12/12/next-generation-grand-vitara-will-use-stretched-version-of-the-kizashi-platform/