Steve - this forum is full of light hearted remarks like that please dont get the hump its all meant in fun
As neil says there is a 135PS van - but only in RWD so the floor would be higher than a FWD.
TBH any Mk6 will be quicker and have more pulling power than the mk5 you already have as they all have turbos. The most common ones seem to be 85PS (front wheel drive) or 90PS (rear wheel drive). Your current MK5 will be 70 or 76PS (assuming its not a turbo).
At uni we had 2 115PS 15 seat minibus' (3500kg max gross weight) which were often loaded up to, and beyond their limits and they really moved! You would be able to get even more power and economy on a mk6 with a remap (PM martynx about this - he is the man in the know).
I would suggest going and looking at a few vans - dont worry too much about the body style initially - just to see how powerful the newer variants are! You could test drive several with different power outputs