Road tax crew cabs

I know this topic has been covered before but has anyone recently tried to get a LWB 4x4 taxed commercial and imported as a cat B vehicle for VRT purposes while keeping the back seats and installing a bulkhead. I know that the cargo area must be more than 45% of the wheelbase length so in a Landcruiser this would mean a cargo area of 1255mm and for Cat B the gross vehicle weight must be below 3500kg's. Can it be done or is the boot space is in most 4x4's too short. Would be nice not to be limited to leaf spring pick up crew cabs...